[PATCH v7 00/21] KVM RISC-V Support

[PATCH v7 00/21] KVM RISC-V Support

[Anup Patel]

This series adds initial KVM RISC-V support. Currently, we are able to boot
RISC-V 64bit Linux Guests with multiple VCPUs.

Few key aspects of KVM RISC-V added by this series are:
1. Minimal possible KVM world-switch which touches only GPRs and few CSRs.
2. Full Guest/VM switch is done via vcpu_get/vcpu_put infrastructure.
3. KVM ONE_REG interface for VCPU register access from user-space.
4. PLIC emulation is done in user-space.
5. Timer and IPI emuation is done in-kernel.
6. MMU notifiers supported.
7. FP lazy save/restore supported.
8. SBI v0.1 emulation for KVM Guest available.

Here's a brief TODO list which we will work upon after this series:
1. Implement recursive stage2 page table programing
2. SBI v0.2 emulation in-kernel
3. SBI v0.2 hart hotplug emulation in-kernel
4. In-kernel PLIC emulation
5. ..... and more .....

This series can be found in riscv_kvm_v7 branch at:
https//github.com/avpatel/linux.git

Our work-in-progress KVMTOOL RISC-V port can be found in riscv_v1 branch at:
https//github.com/avpatel/kvmtool.git

We need OpenSBI with RISC-V hypervisor extension support which can be
found in hyp_ext_changes_v1 branch at:
https://github.com/riscv/opensbi.git

The QEMU RISC-V hypervisor emulation is done by Alistair and is available
in riscv-hyp-work.next branch at:
https://github.com/alistair23/qemu.git

To play around with KVM RISC-V, refer KVM RISC-V wiki at:
https://github.com/kvm-riscv/howto/wiki
https://github.com/kvm-riscv/howto/wiki/KVM-RISCV64-on-QEMU

Changes since v6:
- Rebased patches on Linux-5.3-rc7
- Added "return_handled" in struct kvm_mmio_decode to ensure that
  kvm_riscv_vcpu_mmio_return() updates SEPC only once
- Removed trap_stval parameter from kvm_riscv_vcpu_unpriv_read()
- Updated git repo URL in MAINTAINERS entry

Changes since v5:
- Renamed KVM_REG_RISCV_CONFIG_TIMEBASE register to
  KVM_REG_RISCV_CONFIG_TBFREQ register in ONE_REG interface
- Update SPEC in kvm_riscv_vcpu_mmio_return() for MMIO exits
- Use switch case instead of illegal instruction opcode table for simplicity
- Improve comments in stage2_remote_tlb_flush() for a potential remote TLB
  flush optimization
- Handle all unsupported SBI calls in default case of
  kvm_riscv_vcpu_sbi_ecall() function
- Fixed kvm_riscv_vcpu_sync_interrupts() for software interrupts
- Improved unprivilege reads to handle traps due to Guest stage1 page table
- Added separate patch to document RISC-V specific things in
  Documentation/virt/kvm/api.txt

Changes since v4:
- Rebased patches on Linux-5.3-rc5
- Added Paolo's Acked-by and Reviewed-by
- Updated mailing list in MAINTAINERS entry

Changes since v3:
- Moved patch for ISA bitmap from KVM prep series to this series
- Make vsip_shadow as run-time percpu variable instead of compile-time
- Flush Guest TLBs on all Host CPUs whenever we run-out of VMIDs

Changes since v2:
- Removed references of KVM_REQ_IRQ_PENDING from all patches
- Use kvm->srcu within in-kernel KVM run loop
- Added percpu vsip_shadow to track last value programmed in VSIP CSR
- Added comments about irqs_pending and irqs_pending_mask
- Used kvm_arch_vcpu_runnable() in-place-of kvm_riscv_vcpu_has_interrupt()
  in system_opcode_insn()
- Removed unwanted smp_wmb() in kvm_riscv_stage2_vmid_update()
- Use kvm_flush_remote_tlbs() in kvm_riscv_stage2_vmid_update()
- Use READ_ONCE() in kvm_riscv_stage2_update_hgatp() for vmid

Changes since v1:
- Fixed compile errors in building KVM RISC-V as module
- Removed unused kvm_riscv_halt_guest() and kvm_riscv_resume_guest()
- Set KVM_CAP_SYNC_MMU capability only after MMU notifiers are implemented
- Made vmid_version as unsigned long instead of atomic
- Renamed KVM_REQ_UPDATE_PGTBL to KVM_REQ_UPDATE_HGATP
- Renamed kvm_riscv_stage2_update_pgtbl() to kvm_riscv_stage2_update_hgatp()
- Configure HIDELEG and HEDELEG in kvm_arch_hardware_enable()
- Updated ONE_REG interface for CSR access to user-space
- Removed irqs_pending_lock and use atomic bitops instead
- Added separate patch for FP ONE_REG interface
- Added separate patch for updating MAINTAINERS file

Anup Patel (16):
  KVM: RISC-V: Add KVM_REG_RISCV for ONE_REG interface
  RISC-V: Add bitmap reprensenting ISA features common across CPUs
  RISC-V: Add hypervisor extension related CSR defines
  RISC-V: Add initial skeletal KVM support
  RISC-V: KVM: Implement VCPU create, init and destroy functions
  RISC-V: KVM: Implement VCPU interrupts and requests handling
  RISC-V: KVM: Implement KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctls
  RISC-V: KVM: Implement VCPU world-switch
  RISC-V: KVM: Handle MMIO exits for VCPU
  RISC-V: KVM: Handle WFI exits for VCPU
  RISC-V: KVM: Implement VMID allocator
  RISC-V: KVM: Implement stage2 page table programming
  RISC-V: KVM: Implement MMU notifiers
  RISC-V: KVM: Document RISC-V specific parts of KVM API.
  RISC-V: Enable VIRTIO drivers in RV64 and RV32 defconfig
  RISC-V: KVM: Add MAINTAINERS entry

Atish Patra (5):
  RISC-V: Export few kernel symbols
  RISC-V: KVM: Add timer functionality
  RISC-V: KVM: FP lazy save/restore
  RISC-V: KVM: Implement ONE REG interface for FP registers
  RISC-V: KVM: Add SBI v0.1 support

 Documentation/virt/kvm/api.txt          | 141 +++-
 MAINTAINERS                             |  10 +
 arch/riscv/Kconfig                      |   2 +
 arch/riscv/Makefile                     |   2 +
 arch/riscv/configs/defconfig            |  11 +
 arch/riscv/configs/rv32_defconfig       |  11 +
 arch/riscv/include/asm/csr.h            |  58 ++
 arch/riscv/include/asm/hwcap.h          |  26 +
 arch/riscv/include/asm/kvm_host.h       | 255 ++++++
 arch/riscv/include/asm/kvm_vcpu_timer.h |  30 +
 arch/riscv/include/asm/pgtable-bits.h   |   1 +
 arch/riscv/include/uapi/asm/kvm.h       | 104 +++
 arch/riscv/kernel/asm-offsets.c         | 148 ++++
 arch/riscv/kernel/cpufeature.c          |  79 +-
 arch/riscv/kernel/smp.c                 |   2 +-
 arch/riscv/kernel/time.c                |   1 +
 arch/riscv/kvm/Kconfig                  |  34 +
 arch/riscv/kvm/Makefile                 |  14 +
 arch/riscv/kvm/main.c                   |  92 +++
 arch/riscv/kvm/mmu.c                    | 911 +++++++++++++++++++++
 arch/riscv/kvm/tlb.S                    |  43 +
 arch/riscv/kvm/vcpu.c                   | 998 ++++++++++++++++++++++++
 arch/riscv/kvm/vcpu_exit.c              | 616 +++++++++++++++
 arch/riscv/kvm/vcpu_sbi.c               | 104 +++
 arch/riscv/kvm/vcpu_switch.S            | 376 +++++++++
 arch/riscv/kvm/vcpu_timer.c             | 113 +++
 arch/riscv/kvm/vm.c                     |  86 ++
 arch/riscv/kvm/vmid.c                   | 123 +++
 drivers/clocksource/timer-riscv.c       |   8 +
 include/clocksource/timer-riscv.h       |  16 +
 include/uapi/linux/kvm.h                |   1 +
 31 files changed, 4405 insertions(+), 11 deletions(-)
 create mode 100644 arch/riscv/include/asm/kvm_host.h
 create mode 100644 arch/riscv/include/asm/kvm_vcpu_timer.h
 create mode 100644 arch/riscv/include/uapi/asm/kvm.h
 create mode 100644 arch/riscv/kvm/Kconfig
 create mode 100644 arch/riscv/kvm/Makefile
 create mode 100644 arch/riscv/kvm/main.c
 create mode 100644 arch/riscv/kvm/mmu.c
 create mode 100644 arch/riscv/kvm/tlb.S
 create mode 100644 arch/riscv/kvm/vcpu.c
 create mode 100644 arch/riscv/kvm/vcpu_exit.c
 create mode 100644 arch/riscv/kvm/vcpu_sbi.c
 create mode 100644 arch/riscv/kvm/vcpu_switch.S
 create mode 100644 arch/riscv/kvm/vcpu_timer.c
 create mode 100644 arch/riscv/kvm/vm.c
 create mode 100644 arch/riscv/kvm/vmid.c
 create mode 100644 include/clocksource/timer-riscv.h

--
2.17.1

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[PATCH v7 01/21] KVM: RISC-V: Add KVM_REG_RISCV for ONE_REG interface

[Anup Patel]

We will be using ONE_REG interface accessing VCPU registers from
user-space hence we add KVM_REG_RISCV for RISC-V VCPU registers.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
 include/uapi/linux/kvm.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 5e3f12d5359e..fcaea3c2fc7e 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1142,6 +1142,7 @@ struct kvm_dirty_tlb {
 #define KVM_REG_S390		0x5000000000000000ULL
 #define KVM_REG_ARM64		0x6000000000000000ULL
 #define KVM_REG_MIPS		0x7000000000000000ULL
+#define KVM_REG_RISCV		0x8000000000000000ULL
 
 #define KVM_REG_SIZE_SHIFT	52
 #define KVM_REG_SIZE_MASK	0x00f0000000000000ULL
-- 
2.17.1


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Re: [PATCH v7 01/21] KVM: RISC-V: Add KVM_REG_RISCV for ONE_REG interface

[Paul Walmsley]

On Wed, 4 Sep 2019, Anup Patel wrote:

> We will be using ONE_REG interface accessing VCPU registers from
> user-space hence we add KVM_REG_RISCV for RISC-V VCPU registers.
> 
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> Reviewed-by: Alexander Graf <graf@amazon.com>

Thanks, queued for v5.4-rc.


- Paul

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[PATCH] RISC-V: Enable KVM for RV64 and RV32

[Anup Patel]

DO NOT UPSTREAM !!!!!

Signed-off-by: Anup Patel <anup.patel@wdc.com>
---
 arch/riscv/configs/defconfig      | 2 ++
 arch/riscv/configs/rv32_defconfig | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig
index 420a0dbef386..320a7f1da4fc 100644
--- a/arch/riscv/configs/defconfig
+++ b/arch/riscv/configs/defconfig
@@ -16,6 +16,8 @@ CONFIG_EXPERT=y
 CONFIG_BPF_SYSCALL=y
 CONFIG_SOC_SIFIVE=y
 CONFIG_SMP=y
+CONFIG_VIRTUALIZATION=y
+CONFIG_KVM=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_NET=y
diff --git a/arch/riscv/configs/rv32_defconfig b/arch/riscv/configs/rv32_defconfig
index 87ee6e62b64b..6223e47cc5f0 100644
--- a/arch/riscv/configs/rv32_defconfig
+++ b/arch/riscv/configs/rv32_defconfig
@@ -16,6 +16,8 @@ CONFIG_EXPERT=y
 CONFIG_BPF_SYSCALL=y
 CONFIG_ARCH_RV32I=y
 CONFIG_SMP=y
+CONFIG_VIRTUALIZATION=y
+CONFIG_KVM=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_NET=y
-- 
2.17.1


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Re: [PATCH] RISC-V: Enable KVM for RV64 and RV32

[Anup Patel]

On Wed, Sep 4, 2019 at 9:43 PM Anup Patel <Anup.Patel@wdc.com> wrote:
>
> DO NOT UPSTREAM !!!!!
>
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> ---
>  arch/riscv/configs/defconfig      | 2 ++
>  arch/riscv/configs/rv32_defconfig | 2 ++
>  2 files changed, 4 insertions(+)
>
> diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig
> index 420a0dbef386..320a7f1da4fc 100644
> --- a/arch/riscv/configs/defconfig
> +++ b/arch/riscv/configs/defconfig
> @@ -16,6 +16,8 @@ CONFIG_EXPERT=y
>  CONFIG_BPF_SYSCALL=y
>  CONFIG_SOC_SIFIVE=y
>  CONFIG_SMP=y
> +CONFIG_VIRTUALIZATION=y
> +CONFIG_KVM=y
>  CONFIG_MODULES=y
>  CONFIG_MODULE_UNLOAD=y
>  CONFIG_NET=y
> diff --git a/arch/riscv/configs/rv32_defconfig b/arch/riscv/configs/rv32_defconfig
> index 87ee6e62b64b..6223e47cc5f0 100644
> --- a/arch/riscv/configs/rv32_defconfig
> +++ b/arch/riscv/configs/rv32_defconfig
> @@ -16,6 +16,8 @@ CONFIG_EXPERT=y
>  CONFIG_BPF_SYSCALL=y
>  CONFIG_ARCH_RV32I=y
>  CONFIG_SMP=y
> +CONFIG_VIRTUALIZATION=y
> +CONFIG_KVM=y
>  CONFIG_MODULES=y
>  CONFIG_MODULE_UNLOAD=y
>  CONFIG_NET=y
> --
> 2.17.1
>

Please ignore this patch.

The KVM RISC-V should be disabled by default since it's
experimental currently.

Regards,
Anup

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[PATCH v7 02/21] RISC-V: Add bitmap reprensenting ISA features common across CPUs

[Anup Patel]

This patch adds riscv_isa bitmap which represents Host ISA features
common across all Host CPUs. The riscv_isa is not same as elf_hwcap
because elf_hwcap will only have ISA features relevant for user-space
apps whereas riscv_isa will have ISA features relevant to both kernel
and user-space apps.

One of the use-case for riscv_isa bitmap is in KVM hypervisor where
we will use it to do following operations:

1. Check whether hypervisor extension is available
2. Find ISA features that need to be virtualized (e.g. floating
   point support, vector extension, etc.)

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
 arch/riscv/include/asm/hwcap.h | 26 +++++++++++
 arch/riscv/kernel/cpufeature.c | 79 ++++++++++++++++++++++++++++++++--
 2 files changed, 102 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
index 7ecb7c6a57b1..9b657375aa51 100644
--- a/arch/riscv/include/asm/hwcap.h
+++ b/arch/riscv/include/asm/hwcap.h
@@ -8,6 +8,7 @@
 #ifndef __ASM_HWCAP_H
 #define __ASM_HWCAP_H
 
+#include <linux/bits.h>
 #include <uapi/asm/hwcap.h>
 
 #ifndef __ASSEMBLY__
@@ -22,5 +23,30 @@ enum {
 };
 
 extern unsigned long elf_hwcap;
+
+#define RISCV_ISA_EXT_a		('a' - 'a')
+#define RISCV_ISA_EXT_c		('c' - 'a')
+#define RISCV_ISA_EXT_d		('d' - 'a')
+#define RISCV_ISA_EXT_f		('f' - 'a')
+#define RISCV_ISA_EXT_h		('h' - 'a')
+#define RISCV_ISA_EXT_i		('i' - 'a')
+#define RISCV_ISA_EXT_m		('m' - 'a')
+#define RISCV_ISA_EXT_s		('s' - 'a')
+#define RISCV_ISA_EXT_u		('u' - 'a')
+#define RISCV_ISA_EXT_zicsr	(('z' - 'a') + 1)
+#define RISCV_ISA_EXT_zifencei	(('z' - 'a') + 2)
+#define RISCV_ISA_EXT_zam	(('z' - 'a') + 3)
+#define RISCV_ISA_EXT_ztso	(('z' - 'a') + 4)
+
+#define RISCV_ISA_EXT_MAX	256
+
+unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap);
+
+#define riscv_isa_extension_mask(ext) BIT_MASK(RISCV_ISA_EXT_##ext)
+
+bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit);
+#define riscv_isa_extension_available(isa_bitmap, ext)	\
+	__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_##ext)
+
 #endif
 #endif
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index b1ade9a49347..4ce71ce5e290 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -6,21 +6,64 @@
  * Copyright (C) 2017 SiFive
  */
 
+#include <linux/bitmap.h>
 #include <linux/of.h>
 #include <asm/processor.h>
 #include <asm/hwcap.h>
 #include <asm/smp.h>
 
 unsigned long elf_hwcap __read_mostly;
+
+/* Host ISA bitmap */
+static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
+
 #ifdef CONFIG_FPU
 bool has_fpu __read_mostly;
 #endif
 
+/**
+ * riscv_isa_extension_base - Get base extension word
+ *
+ * @isa_bitmap ISA bitmap to use
+ * @returns base extension word as unsigned long value
+ *
+ * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
+ */
+unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap)
+{
+	if (!isa_bitmap)
+		return riscv_isa[0];
+	return isa_bitmap[0];
+}
+EXPORT_SYMBOL_GPL(riscv_isa_extension_base);
+
+/**
+ * __riscv_isa_extension_available - Check whether given extension
+ * is available or not
+ *
+ * @isa_bitmap ISA bitmap to use
+ * @bit bit position of the desired extension
+ * @returns true or false
+ *
+ * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
+ */
+bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit)
+{
+	const unsigned long *bmap = (isa_bitmap) ? isa_bitmap : riscv_isa;
+
+	if (bit >= RISCV_ISA_EXT_MAX)
+		return false;
+
+	return test_bit(bit, bmap) ? true : false;
+}
+EXPORT_SYMBOL_GPL(__riscv_isa_extension_available);
+
 void riscv_fill_hwcap(void)
 {
 	struct device_node *node;
 	const char *isa;
-	size_t i;
+	char print_str[BITS_PER_LONG+1];
+	size_t i, j, isa_len;
 	static unsigned long isa2hwcap[256] = {0};
 
 	isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;
@@ -32,8 +75,11 @@ void riscv_fill_hwcap(void)
 
 	elf_hwcap = 0;
 
+	bitmap_zero(riscv_isa, RISCV_ISA_EXT_MAX);
+
 	for_each_of_cpu_node(node) {
 		unsigned long this_hwcap = 0;
+		unsigned long this_isa = 0;
 
 		if (riscv_of_processor_hartid(node) < 0)
 			continue;
@@ -43,8 +89,20 @@ void riscv_fill_hwcap(void)
 			continue;
 		}
 
-		for (i = 0; i < strlen(isa); ++i)
+		i = 0;
+		isa_len = strlen(isa);
+#if defined(CONFIG_32BIT)
+		if (!strncmp(isa, "rv32", 4))
+			i += 4;
+#elif defined(CONFIG_64BIT)
+		if (!strncmp(isa, "rv64", 4))
+			i += 4;
+#endif
+		for (; i < isa_len; ++i) {
 			this_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
+			if ('a' <= isa[i] && isa[i] <= 'z')
+				this_isa |= (1UL << (isa[i] - 'a'));
+		}
 
 		/*
 		 * All "okay" hart should have same isa. Set HWCAP based on
@@ -55,6 +113,11 @@ void riscv_fill_hwcap(void)
 			elf_hwcap &= this_hwcap;
 		else
 			elf_hwcap = this_hwcap;
+
+		if (riscv_isa[0])
+			riscv_isa[0] &= this_isa;
+		else
+			riscv_isa[0] = this_isa;
 	}
 
 	/* We don't support systems with F but without D, so mask those out
@@ -64,7 +127,17 @@ void riscv_fill_hwcap(void)
 		elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
 	}
 
-	pr_info("elf_hwcap is 0x%lx\n", elf_hwcap);
+	memset(print_str, 0, sizeof(print_str));
+	for (i = 0, j = 0; i < BITS_PER_LONG; i++)
+		if (riscv_isa[0] & BIT_MASK(i))
+			print_str[j++] = (char)('a' + i);
+	pr_info("riscv: ISA extensions %s\n", print_str);
+
+	memset(print_str, 0, sizeof(print_str));
+	for (i = 0, j = 0; i < BITS_PER_LONG; i++)
+		if (elf_hwcap & BIT_MASK(i))
+			print_str[j++] = (char)('a' + i);
+	pr_info("riscv: ELF capabilities %s\n", print_str);
 
 #ifdef CONFIG_FPU
 	if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))
-- 
2.17.1


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Re: [PATCH v7 02/21] RISC-V: Add bitmap reprensenting ISA features common across CPUs

[Anup Patel]

Hi Paul,

On Wed, Sep 4, 2019 at 9:43 PM Anup Patel <Anup.Patel@wdc.com> wrote:
>
> This patch adds riscv_isa bitmap which represents Host ISA features
> common across all Host CPUs. The riscv_isa is not same as elf_hwcap
> because elf_hwcap will only have ISA features relevant for user-space
> apps whereas riscv_isa will have ISA features relevant to both kernel
> and user-space apps.
>
> One of the use-case for riscv_isa bitmap is in KVM hypervisor where
> we will use it to do following operations:
>
> 1. Check whether hypervisor extension is available
> 2. Find ISA features that need to be virtualized (e.g. floating
>    point support, vector extension, etc.)

I had addressed your previous comments on this patch by
making riscv_isa as bitmap to cover Z-extensions.

Please review it again.

Regards,
Anup

>
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Reviewed-by: Alexander Graf <graf@amazon.com>
> ---
>  arch/riscv/include/asm/hwcap.h | 26 +++++++++++
>  arch/riscv/kernel/cpufeature.c | 79 ++++++++++++++++++++++++++++++++--
>  2 files changed, 102 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
> index 7ecb7c6a57b1..9b657375aa51 100644
> --- a/arch/riscv/include/asm/hwcap.h
> +++ b/arch/riscv/include/asm/hwcap.h
> @@ -8,6 +8,7 @@
>  #ifndef __ASM_HWCAP_H
>  #define __ASM_HWCAP_H
>
> +#include <linux/bits.h>
>  #include <uapi/asm/hwcap.h>
>
>  #ifndef __ASSEMBLY__
> @@ -22,5 +23,30 @@ enum {
>  };
>
>  extern unsigned long elf_hwcap;
> +
> +#define RISCV_ISA_EXT_a                ('a' - 'a')
> +#define RISCV_ISA_EXT_c                ('c' - 'a')
> +#define RISCV_ISA_EXT_d                ('d' - 'a')
> +#define RISCV_ISA_EXT_f                ('f' - 'a')
> +#define RISCV_ISA_EXT_h                ('h' - 'a')
> +#define RISCV_ISA_EXT_i                ('i' - 'a')
> +#define RISCV_ISA_EXT_m                ('m' - 'a')
> +#define RISCV_ISA_EXT_s                ('s' - 'a')
> +#define RISCV_ISA_EXT_u                ('u' - 'a')
> +#define RISCV_ISA_EXT_zicsr    (('z' - 'a') + 1)
> +#define RISCV_ISA_EXT_zifencei (('z' - 'a') + 2)
> +#define RISCV_ISA_EXT_zam      (('z' - 'a') + 3)
> +#define RISCV_ISA_EXT_ztso     (('z' - 'a') + 4)
> +
> +#define RISCV_ISA_EXT_MAX      256
> +
> +unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap);
> +
> +#define riscv_isa_extension_mask(ext) BIT_MASK(RISCV_ISA_EXT_##ext)
> +
> +bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit);
> +#define riscv_isa_extension_available(isa_bitmap, ext) \
> +       __riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_##ext)
> +
>  #endif
>  #endif
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index b1ade9a49347..4ce71ce5e290 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -6,21 +6,64 @@
>   * Copyright (C) 2017 SiFive
>   */
>
> +#include <linux/bitmap.h>
>  #include <linux/of.h>
>  #include <asm/processor.h>
>  #include <asm/hwcap.h>
>  #include <asm/smp.h>
>
>  unsigned long elf_hwcap __read_mostly;
> +
> +/* Host ISA bitmap */
> +static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
> +
>  #ifdef CONFIG_FPU
>  bool has_fpu __read_mostly;
>  #endif
>
> +/**
> + * riscv_isa_extension_base - Get base extension word
> + *
> + * @isa_bitmap ISA bitmap to use
> + * @returns base extension word as unsigned long value
> + *
> + * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
> + */
> +unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap)
> +{
> +       if (!isa_bitmap)
> +               return riscv_isa[0];
> +       return isa_bitmap[0];
> +}
> +EXPORT_SYMBOL_GPL(riscv_isa_extension_base);
> +
> +/**
> + * __riscv_isa_extension_available - Check whether given extension
> + * is available or not
> + *
> + * @isa_bitmap ISA bitmap to use
> + * @bit bit position of the desired extension
> + * @returns true or false
> + *
> + * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
> + */
> +bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit)
> +{
> +       const unsigned long *bmap = (isa_bitmap) ? isa_bitmap : riscv_isa;
> +
> +       if (bit >= RISCV_ISA_EXT_MAX)
> +               return false;
> +
> +       return test_bit(bit, bmap) ? true : false;
> +}
> +EXPORT_SYMBOL_GPL(__riscv_isa_extension_available);
> +
>  void riscv_fill_hwcap(void)
>  {
>         struct device_node *node;
>         const char *isa;
> -       size_t i;
> +       char print_str[BITS_PER_LONG+1];
> +       size_t i, j, isa_len;
>         static unsigned long isa2hwcap[256] = {0};
>
>         isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;
> @@ -32,8 +75,11 @@ void riscv_fill_hwcap(void)
>
>         elf_hwcap = 0;
>
> +       bitmap_zero(riscv_isa, RISCV_ISA_EXT_MAX);
> +
>         for_each_of_cpu_node(node) {
>                 unsigned long this_hwcap = 0;
> +               unsigned long this_isa = 0;
>
>                 if (riscv_of_processor_hartid(node) < 0)
>                         continue;
> @@ -43,8 +89,20 @@ void riscv_fill_hwcap(void)
>                         continue;
>                 }
>
> -               for (i = 0; i < strlen(isa); ++i)
> +               i = 0;
> +               isa_len = strlen(isa);
> +#if defined(CONFIG_32BIT)
> +               if (!strncmp(isa, "rv32", 4))
> +                       i += 4;
> +#elif defined(CONFIG_64BIT)
> +               if (!strncmp(isa, "rv64", 4))
> +                       i += 4;
> +#endif
> +               for (; i < isa_len; ++i) {
>                         this_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
> +                       if ('a' <= isa[i] && isa[i] <= 'z')
> +                               this_isa |= (1UL << (isa[i] - 'a'));
> +               }
>
>                 /*
>                  * All "okay" hart should have same isa. Set HWCAP based on
> @@ -55,6 +113,11 @@ void riscv_fill_hwcap(void)
>                         elf_hwcap &= this_hwcap;
>                 else
>                         elf_hwcap = this_hwcap;
> +
> +               if (riscv_isa[0])
> +                       riscv_isa[0] &= this_isa;
> +               else
> +                       riscv_isa[0] = this_isa;
>         }
>
>         /* We don't support systems with F but without D, so mask those out
> @@ -64,7 +127,17 @@ void riscv_fill_hwcap(void)
>                 elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
>         }
>
> -       pr_info("elf_hwcap is 0x%lx\n", elf_hwcap);
> +       memset(print_str, 0, sizeof(print_str));
> +       for (i = 0, j = 0; i < BITS_PER_LONG; i++)
> +               if (riscv_isa[0] & BIT_MASK(i))
> +                       print_str[j++] = (char)('a' + i);
> +       pr_info("riscv: ISA extensions %s\n", print_str);
> +
> +       memset(print_str, 0, sizeof(print_str));
> +       for (i = 0, j = 0; i < BITS_PER_LONG; i++)
> +               if (elf_hwcap & BIT_MASK(i))
> +                       print_str[j++] = (char)('a' + i);
> +       pr_info("riscv: ELF capabilities %s\n", print_str);
>
>  #ifdef CONFIG_FPU
>         if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))
> --
> 2.17.1
>

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Re: [PATCH v7 02/21] RISC-V: Add bitmap reprensenting ISA features common across CPUs

[Paul Walmsley]

Hi Anup,

Thanks for changing this to use a bitmap.  A few comments below -

On Wed, 4 Sep 2019, Anup Patel wrote:

> This patch adds riscv_isa bitmap which represents Host ISA features
> common across all Host CPUs. The riscv_isa is not same as elf_hwcap
> because elf_hwcap will only have ISA features relevant for user-space
> apps whereas riscv_isa will have ISA features relevant to both kernel
> and user-space apps.
> 
> One of the use-case for riscv_isa bitmap is in KVM hypervisor where
> we will use it to do following operations:
> 
> 1. Check whether hypervisor extension is available
> 2. Find ISA features that need to be virtualized (e.g. floating
>    point support, vector extension, etc.)
> 
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Reviewed-by: Alexander Graf <graf@amazon.com>
> ---
>  arch/riscv/include/asm/hwcap.h | 26 +++++++++++
>  arch/riscv/kernel/cpufeature.c | 79 ++++++++++++++++++++++++++++++++--
>  2 files changed, 102 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
> index 7ecb7c6a57b1..9b657375aa51 100644
> --- a/arch/riscv/include/asm/hwcap.h
> +++ b/arch/riscv/include/asm/hwcap.h
> @@ -8,6 +8,7 @@
>  #ifndef __ASM_HWCAP_H
>  #define __ASM_HWCAP_H
>  
> +#include <linux/bits.h>
>  #include <uapi/asm/hwcap.h>
>  
>  #ifndef __ASSEMBLY__
> @@ -22,5 +23,30 @@ enum {
>  };
>  
>  extern unsigned long elf_hwcap;
> +
> +#define RISCV_ISA_EXT_a		('a' - 'a')
> +#define RISCV_ISA_EXT_c		('c' - 'a')
> +#define RISCV_ISA_EXT_d		('d' - 'a')
> +#define RISCV_ISA_EXT_f		('f' - 'a')
> +#define RISCV_ISA_EXT_h		('h' - 'a')
> +#define RISCV_ISA_EXT_i		('i' - 'a')
> +#define RISCV_ISA_EXT_m		('m' - 'a')
> +#define RISCV_ISA_EXT_s		('s' - 'a')
> +#define RISCV_ISA_EXT_u		('u' - 'a')
> +#define RISCV_ISA_EXT_zicsr	(('z' - 'a') + 1)
> +#define RISCV_ISA_EXT_zifencei	(('z' - 'a') + 2)
> +#define RISCV_ISA_EXT_zam	(('z' - 'a') + 3)
> +#define RISCV_ISA_EXT_ztso	(('z' - 'a') + 4)

If we add the Z extensions here, it's probably best if we drop Zam from 
this list.  The rationale is, as maintainers, we're planning to hold off 
on merging any support for extensions or modules that aren't in the 
"frozen" or "ratified" states, and according to the RISC-V specs, Zicsr, 
Zifencei, and Ztso are all either frozen or ratified.  However, see 
below -

> +
> +#define RISCV_ISA_EXT_MAX	256
> +
> +unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap);
> +
> +#define riscv_isa_extension_mask(ext) BIT_MASK(RISCV_ISA_EXT_##ext)
> +
> +bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit);
> +#define riscv_isa_extension_available(isa_bitmap, ext)	\
> +	__riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_##ext)
> +
>  #endif
>  #endif
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index b1ade9a49347..4ce71ce5e290 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -6,21 +6,64 @@
>   * Copyright (C) 2017 SiFive
>   */
>  
> +#include <linux/bitmap.h>
>  #include <linux/of.h>
>  #include <asm/processor.h>
>  #include <asm/hwcap.h>
>  #include <asm/smp.h>
>  
>  unsigned long elf_hwcap __read_mostly;
> +
> +/* Host ISA bitmap */
> +static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
> +
>  #ifdef CONFIG_FPU
>  bool has_fpu __read_mostly;
>  #endif
>  
> +/**
> + * riscv_isa_extension_base - Get base extension word
> + *
> + * @isa_bitmap ISA bitmap to use
> + * @returns base extension word as unsigned long value
> + *
> + * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
> + */

Am happy to see comments that can be automatically parsed, but could you 
reformat them into kernel-doc format? 

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/doc-guide/kernel-doc.rst

> +unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap)
> +{
> +	if (!isa_bitmap)
> +		return riscv_isa[0];
> +	return isa_bitmap[0];
> +}
> +EXPORT_SYMBOL_GPL(riscv_isa_extension_base);
> +
> +/**
> + * __riscv_isa_extension_available - Check whether given extension
> + * is available or not
> + *
> + * @isa_bitmap ISA bitmap to use
> + * @bit bit position of the desired extension
> + * @returns true or false
> + *
> + * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
> + */

Same comment as above.

> +bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit)
> +{
> +	const unsigned long *bmap = (isa_bitmap) ? isa_bitmap : riscv_isa;
> +
> +	if (bit >= RISCV_ISA_EXT_MAX)
> +		return false;
> +
> +	return test_bit(bit, bmap) ? true : false;
> +}
> +EXPORT_SYMBOL_GPL(__riscv_isa_extension_available);
> +
>  void riscv_fill_hwcap(void)
>  {
>  	struct device_node *node;
>  	const char *isa;
> -	size_t i;
> +	char print_str[BITS_PER_LONG+1];
> +	size_t i, j, isa_len;
>  	static unsigned long isa2hwcap[256] = {0};
>  
>  	isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;
> @@ -32,8 +75,11 @@ void riscv_fill_hwcap(void)
>  
>  	elf_hwcap = 0;
>  
> +	bitmap_zero(riscv_isa, RISCV_ISA_EXT_MAX);
> +
>  	for_each_of_cpu_node(node) {
>  		unsigned long this_hwcap = 0;
> +		unsigned long this_isa = 0;
>  
>  		if (riscv_of_processor_hartid(node) < 0)
>  			continue;
> @@ -43,8 +89,20 @@ void riscv_fill_hwcap(void)
>  			continue;
>  		}
>  
> -		for (i = 0; i < strlen(isa); ++i)
> +		i = 0;
> +		isa_len = strlen(isa);
> +#if defined(CONFIG_32BIT)
> +		if (!strncmp(isa, "rv32", 4))
> +			i += 4;
> +#elif defined(CONFIG_64BIT)
> +		if (!strncmp(isa, "rv64", 4))
> +			i += 4;
> +#endif
> +		for (; i < isa_len; ++i) {
>  			this_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
> +			if ('a' <= isa[i] && isa[i] <= 'z')
> +				this_isa |= (1UL << (isa[i] - 'a'));

Continuing from the earlier comment, this code won't properly handle the X 
and Z prefix extensions.  So maybe for the time being, we should just drop 
the lines mentioned earlier that imply that we can parse Z-prefix 
extensions, and change this line so it ignores X and Z letters?

Then a subsequent patch can add support for more complicated extension 
string parsing.


> +		}
>  
>  		/*
>  		 * All "okay" hart should have same isa. Set HWCAP based on
> @@ -55,6 +113,11 @@ void riscv_fill_hwcap(void)
>  			elf_hwcap &= this_hwcap;
>  		else
>  			elf_hwcap = this_hwcap;
> +
> +		if (riscv_isa[0])
> +			riscv_isa[0] &= this_isa;
> +		else
> +			riscv_isa[0] = this_isa;
>  	}
>  
>  	/* We don't support systems with F but without D, so mask those out
> @@ -64,7 +127,17 @@ void riscv_fill_hwcap(void)
>  		elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
>  	}
>  
> -	pr_info("elf_hwcap is 0x%lx\n", elf_hwcap);
> +	memset(print_str, 0, sizeof(print_str));
> +	for (i = 0, j = 0; i < BITS_PER_LONG; i++)
> +		if (riscv_isa[0] & BIT_MASK(i))
> +			print_str[j++] = (char)('a' + i);
> +	pr_info("riscv: ISA extensions %s\n", print_str);
> +
> +	memset(print_str, 0, sizeof(print_str));
> +	for (i = 0, j = 0; i < BITS_PER_LONG; i++)
> +		if (elf_hwcap & BIT_MASK(i))
> +			print_str[j++] = (char)('a' + i);
> +	pr_info("riscv: ELF capabilities %s\n", print_str);
>  
>  #ifdef CONFIG_FPU
>  	if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))
> -- 
> 2.17.1
> 
> 


- Paul

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Re: [PATCH v7 02/21] RISC-V: Add bitmap reprensenting ISA features common across CPUs

[Anup Patel]

On Sat, Sep 21, 2019 at 3:31 PM Paul Walmsley <paul.walmsley@sifive.com> wrote:
>
> Hi Anup,
>
> Thanks for changing this to use a bitmap.  A few comments below -
>
> On Wed, 4 Sep 2019, Anup Patel wrote:
>
> > This patch adds riscv_isa bitmap which represents Host ISA features
> > common across all Host CPUs. The riscv_isa is not same as elf_hwcap
> > because elf_hwcap will only have ISA features relevant for user-space
> > apps whereas riscv_isa will have ISA features relevant to both kernel
> > and user-space apps.
> >
> > One of the use-case for riscv_isa bitmap is in KVM hypervisor where
> > we will use it to do following operations:
> >
> > 1. Check whether hypervisor extension is available
> > 2. Find ISA features that need to be virtualized (e.g. floating
> >    point support, vector extension, etc.)
> >
> > Signed-off-by: Anup Patel <anup.patel@wdc.com>
> > Signed-off-by: Atish Patra <atish.patra@wdc.com>
> > Reviewed-by: Alexander Graf <graf@amazon.com>
> > ---
> >  arch/riscv/include/asm/hwcap.h | 26 +++++++++++
> >  arch/riscv/kernel/cpufeature.c | 79 ++++++++++++++++++++++++++++++++--
> >  2 files changed, 102 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/riscv/include/asm/hwcap.h b/arch/riscv/include/asm/hwcap.h
> > index 7ecb7c6a57b1..9b657375aa51 100644
> > --- a/arch/riscv/include/asm/hwcap.h
> > +++ b/arch/riscv/include/asm/hwcap.h
> > @@ -8,6 +8,7 @@
> >  #ifndef __ASM_HWCAP_H
> >  #define __ASM_HWCAP_H
> >
> > +#include <linux/bits.h>
> >  #include <uapi/asm/hwcap.h>
> >
> >  #ifndef __ASSEMBLY__
> > @@ -22,5 +23,30 @@ enum {
> >  };
> >
> >  extern unsigned long elf_hwcap;
> > +
> > +#define RISCV_ISA_EXT_a              ('a' - 'a')
> > +#define RISCV_ISA_EXT_c              ('c' - 'a')
> > +#define RISCV_ISA_EXT_d              ('d' - 'a')
> > +#define RISCV_ISA_EXT_f              ('f' - 'a')
> > +#define RISCV_ISA_EXT_h              ('h' - 'a')
> > +#define RISCV_ISA_EXT_i              ('i' - 'a')
> > +#define RISCV_ISA_EXT_m              ('m' - 'a')
> > +#define RISCV_ISA_EXT_s              ('s' - 'a')
> > +#define RISCV_ISA_EXT_u              ('u' - 'a')
> > +#define RISCV_ISA_EXT_zicsr  (('z' - 'a') + 1)
> > +#define RISCV_ISA_EXT_zifencei       (('z' - 'a') + 2)
> > +#define RISCV_ISA_EXT_zam    (('z' - 'a') + 3)
> > +#define RISCV_ISA_EXT_ztso   (('z' - 'a') + 4)
>
> If we add the Z extensions here, it's probably best if we drop Zam from
> this list.  The rationale is, as maintainers, we're planning to hold off
> on merging any support for extensions or modules that aren't in the
> "frozen" or "ratified" states, and according to the RISC-V specs, Zicsr,
> Zifencei, and Ztso are all either frozen or ratified.  However, see
> below -

No problem, I will remove Zam define.

Please add documentation under Documentation/riscv regarding the
policy of not merging support for RISC-V extensions which aren't in
"frozen" or "ratified" state.

>
> > +
> > +#define RISCV_ISA_EXT_MAX    256
> > +
> > +unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap);
> > +
> > +#define riscv_isa_extension_mask(ext) BIT_MASK(RISCV_ISA_EXT_##ext)
> > +
> > +bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit);
> > +#define riscv_isa_extension_available(isa_bitmap, ext)       \
> > +     __riscv_isa_extension_available(isa_bitmap, RISCV_ISA_EXT_##ext)
> > +
> >  #endif
> >  #endif
> > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> > index b1ade9a49347..4ce71ce5e290 100644
> > --- a/arch/riscv/kernel/cpufeature.c
> > +++ b/arch/riscv/kernel/cpufeature.c
> > @@ -6,21 +6,64 @@
> >   * Copyright (C) 2017 SiFive
> >   */
> >
> > +#include <linux/bitmap.h>
> >  #include <linux/of.h>
> >  #include <asm/processor.h>
> >  #include <asm/hwcap.h>
> >  #include <asm/smp.h>
> >
> >  unsigned long elf_hwcap __read_mostly;
> > +
> > +/* Host ISA bitmap */
> > +static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
> > +
> >  #ifdef CONFIG_FPU
> >  bool has_fpu __read_mostly;
> >  #endif
> >
> > +/**
> > + * riscv_isa_extension_base - Get base extension word
> > + *
> > + * @isa_bitmap ISA bitmap to use
> > + * @returns base extension word as unsigned long value
> > + *
> > + * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
> > + */
>
> Am happy to see comments that can be automatically parsed, but could you
> reformat them into kernel-doc format?
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/doc-guide/kernel-doc.rst

Sure, I will update comments as-per kernel-doc.rst.

>
> > +unsigned long riscv_isa_extension_base(const unsigned long *isa_bitmap)
> > +{
> > +     if (!isa_bitmap)
> > +             return riscv_isa[0];
> > +     return isa_bitmap[0];
> > +}
> > +EXPORT_SYMBOL_GPL(riscv_isa_extension_base);
> > +
> > +/**
> > + * __riscv_isa_extension_available - Check whether given extension
> > + * is available or not
> > + *
> > + * @isa_bitmap ISA bitmap to use
> > + * @bit bit position of the desired extension
> > + * @returns true or false
> > + *
> > + * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
> > + */
>
> Same comment as above.

Okay, I will update.

>
> > +bool __riscv_isa_extension_available(const unsigned long *isa_bitmap, int bit)
> > +{
> > +     const unsigned long *bmap = (isa_bitmap) ? isa_bitmap : riscv_isa;
> > +
> > +     if (bit >= RISCV_ISA_EXT_MAX)
> > +             return false;
> > +
> > +     return test_bit(bit, bmap) ? true : false;
> > +}
> > +EXPORT_SYMBOL_GPL(__riscv_isa_extension_available);
> > +
> >  void riscv_fill_hwcap(void)
> >  {
> >       struct device_node *node;
> >       const char *isa;
> > -     size_t i;
> > +     char print_str[BITS_PER_LONG+1];
> > +     size_t i, j, isa_len;
> >       static unsigned long isa2hwcap[256] = {0};
> >
> >       isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;
> > @@ -32,8 +75,11 @@ void riscv_fill_hwcap(void)
> >
> >       elf_hwcap = 0;
> >
> > +     bitmap_zero(riscv_isa, RISCV_ISA_EXT_MAX);
> > +
> >       for_each_of_cpu_node(node) {
> >               unsigned long this_hwcap = 0;
> > +             unsigned long this_isa = 0;
> >
> >               if (riscv_of_processor_hartid(node) < 0)
> >                       continue;
> > @@ -43,8 +89,20 @@ void riscv_fill_hwcap(void)
> >                       continue;
> >               }
> >
> > -             for (i = 0; i < strlen(isa); ++i)
> > +             i = 0;
> > +             isa_len = strlen(isa);
> > +#if defined(CONFIG_32BIT)
> > +             if (!strncmp(isa, "rv32", 4))
> > +                     i += 4;
> > +#elif defined(CONFIG_64BIT)
> > +             if (!strncmp(isa, "rv64", 4))
> > +                     i += 4;
> > +#endif
> > +             for (; i < isa_len; ++i) {
> >                       this_hwcap |= isa2hwcap[(unsigned char)(isa[i])];
> > +                     if ('a' <= isa[i] && isa[i] <= 'z')
> > +                             this_isa |= (1UL << (isa[i] - 'a'));
>
> Continuing from the earlier comment, this code won't properly handle the X
> and Z prefix extensions.  So maybe for the time being, we should just drop
> the lines mentioned earlier that imply that we can parse Z-prefix
> extensions, and change this line so it ignores X and Z letters?
>
> Then a subsequent patch can add support for more complicated extension
> string parsing.

Okay, we sill not parse 'x' and 'z' bits (which can be added later for
X and Z prefix extensions).

>
>
> > +             }
> >
> >               /*
> >                * All "okay" hart should have same isa. Set HWCAP based on
> > @@ -55,6 +113,11 @@ void riscv_fill_hwcap(void)
> >                       elf_hwcap &= this_hwcap;
> >               else
> >                       elf_hwcap = this_hwcap;
> > +
> > +             if (riscv_isa[0])
> > +                     riscv_isa[0] &= this_isa;
> > +             else
> > +                     riscv_isa[0] = this_isa;
> >       }
> >
> >       /* We don't support systems with F but without D, so mask those out
> > @@ -64,7 +127,17 @@ void riscv_fill_hwcap(void)
> >               elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
> >       }
> >
> > -     pr_info("elf_hwcap is 0x%lx\n", elf_hwcap);
> > +     memset(print_str, 0, sizeof(print_str));
> > +     for (i = 0, j = 0; i < BITS_PER_LONG; i++)
> > +             if (riscv_isa[0] & BIT_MASK(i))
> > +                     print_str[j++] = (char)('a' + i);
> > +     pr_info("riscv: ISA extensions %s\n", print_str);
> > +
> > +     memset(print_str, 0, sizeof(print_str));
> > +     for (i = 0, j = 0; i < BITS_PER_LONG; i++)
> > +             if (elf_hwcap & BIT_MASK(i))
> > +                     print_str[j++] = (char)('a' + i);
> > +     pr_info("riscv: ELF capabilities %s\n", print_str);
> >
> >  #ifdef CONFIG_FPU
> >       if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))
> > --
> > 2.17.1
> >
> >
>
>
> - Paul

Regards,
Anup

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Re: [PATCH v7 02/21] RISC-V: Add bitmap reprensenting ISA features common across CPUs

[Alistair Francis]

On Sat, 2019-09-21 at 03:01 -0700, Paul Walmsley wrote:
> Hi Anup,
> 
> Thanks for changing this to use a bitmap.  A few comments below -
> 
> On Wed, 4 Sep 2019, Anup Patel wrote:
> 
> > This patch adds riscv_isa bitmap which represents Host ISA features
> > common across all Host CPUs. The riscv_isa is not same as elf_hwcap
> > because elf_hwcap will only have ISA features relevant for user-
> > space
> > apps whereas riscv_isa will have ISA features relevant to both
> > kernel
> > and user-space apps.
> > 
> > One of the use-case for riscv_isa bitmap is in KVM hypervisor where
> > we will use it to do following operations:
> > 
> > 1. Check whether hypervisor extension is available
> > 2. Find ISA features that need to be virtualized (e.g. floating
> >    point support, vector extension, etc.)
> > 
> > Signed-off-by: Anup Patel <anup.patel@wdc.com>
> > Signed-off-by: Atish Patra <atish.patra@wdc.com>
> > Reviewed-by: Alexander Graf <graf@amazon.com>
> > ---
> >  arch/riscv/include/asm/hwcap.h | 26 +++++++++++
> >  arch/riscv/kernel/cpufeature.c | 79
> > ++++++++++++++++++++++++++++++++--
> >  2 files changed, 102 insertions(+), 3 deletions(-)
> > 
> > diff --git a/arch/riscv/include/asm/hwcap.h
> > b/arch/riscv/include/asm/hwcap.h
> > index 7ecb7c6a57b1..9b657375aa51 100644
> > --- a/arch/riscv/include/asm/hwcap.h
> > +++ b/arch/riscv/include/asm/hwcap.h
> > @@ -8,6 +8,7 @@
> >  #ifndef __ASM_HWCAP_H
> >  #define __ASM_HWCAP_H
> >  
> > +#include <linux/bits.h>
> >  #include <uapi/asm/hwcap.h>
> >  
> >  #ifndef __ASSEMBLY__
> > @@ -22,5 +23,30 @@ enum {
> >  };
> >  
> >  extern unsigned long elf_hwcap;
> > +
> > +#define RISCV_ISA_EXT_a		('a' - 'a')
> > +#define RISCV_ISA_EXT_c		('c' - 'a')
> > +#define RISCV_ISA_EXT_d		('d' - 'a')
> > +#define RISCV_ISA_EXT_f		('f' - 'a')
> > +#define RISCV_ISA_EXT_h		('h' - 'a')
> > +#define RISCV_ISA_EXT_i		('i' - 'a')
> > +#define RISCV_ISA_EXT_m		('m' - 'a')
> > +#define RISCV_ISA_EXT_s		('s' - 'a')
> > +#define RISCV_ISA_EXT_u		('u' - 'a')
> > +#define RISCV_ISA_EXT_zicsr	(('z' - 'a') + 1)
> > +#define RISCV_ISA_EXT_zifencei	(('z' - 'a') + 2)
> > +#define RISCV_ISA_EXT_zam	(('z' - 'a') + 3)
> > +#define RISCV_ISA_EXT_ztso	(('z' - 'a') + 4)
> 
> If we add the Z extensions here, it's probably best if we drop Zam
> from 
> this list.  The rationale is, as maintainers, we're planning to hold
> off 
> on merging any support for extensions or modules that aren't in the 
> "frozen" or "ratified" states, and according to the RISC-V specs,
> Zicsr, 
> Zifencei, and Ztso are all either frozen or ratified.  However, see 
> below -

Hey Paul,

I think that this should be documented somewhere in the kernel tree. In
QEMU land we have decieded that draft extensions will be accepted and
there are currently two extension series on list (Hypervisor from WDC
and Vector from CSKY). I suspect as RISC-V grows there are going to be
more and more groups that are interested in some specific extension and
want it upstream. In this case it makes sense to have it very clearly
documeneted so that everyone knows what will/won't be accepted.

If it's clearly documented then everyone will be on the same page as to
what will/won't be accepted by individual projects. As a side note I'll
probably look at adding something for QEMU as well :)

Alistair

> 
> > +
> > +#define RISCV_ISA_EXT_MAX	256
> > +
> > +unsigned long riscv_isa_extension_base(const unsigned long
> > *isa_bitmap);
> > +
> > +#define riscv_isa_extension_mask(ext)
> > BIT_MASK(RISCV_ISA_EXT_##ext)
> > +
> > +bool __riscv_isa_extension_available(const unsigned long
> > *isa_bitmap, int bit);
> > +#define riscv_isa_extension_available(isa_bitmap, ext)	\
> > +	__riscv_isa_extension_available(isa_bitmap,
> > RISCV_ISA_EXT_##ext)
> > +
> >  #endif
> >  #endif
> > diff --git a/arch/riscv/kernel/cpufeature.c
> > b/arch/riscv/kernel/cpufeature.c
> > index b1ade9a49347..4ce71ce5e290 100644
> > --- a/arch/riscv/kernel/cpufeature.c
> > +++ b/arch/riscv/kernel/cpufeature.c
> > @@ -6,21 +6,64 @@
> >   * Copyright (C) 2017 SiFive
> >   */
> >  
> > +#include <linux/bitmap.h>
> >  #include <linux/of.h>
> >  #include <asm/processor.h>
> >  #include <asm/hwcap.h>
> >  #include <asm/smp.h>
> >  
> >  unsigned long elf_hwcap __read_mostly;
> > +
> > +/* Host ISA bitmap */
> > +static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
> > +
> >  #ifdef CONFIG_FPU
> >  bool has_fpu __read_mostly;
> >  #endif
> >  
> > +/**
> > + * riscv_isa_extension_base - Get base extension word
> > + *
> > + * @isa_bitmap ISA bitmap to use
> > + * @returns base extension word as unsigned long value
> > + *
> > + * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
> > + */
> 
> Am happy to see comments that can be automatically parsed, but could
> you 
> reformat them into kernel-doc format? 
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/doc-guide/kernel-doc.rst
> 
> > +unsigned long riscv_isa_extension_base(const unsigned long
> > *isa_bitmap)
> > +{
> > +	if (!isa_bitmap)
> > +		return riscv_isa[0];
> > +	return isa_bitmap[0];
> > +}
> > +EXPORT_SYMBOL_GPL(riscv_isa_extension_base);
> > +
> > +/**
> > + * __riscv_isa_extension_available - Check whether given extension
> > + * is available or not
> > + *
> > + * @isa_bitmap ISA bitmap to use
> > + * @bit bit position of the desired extension
> > + * @returns true or false
> > + *
> > + * NOTE: If isa_bitmap is NULL then Host ISA bitmap will be used.
> > + */
> 
> Same comment as above.
> 
> > +bool __riscv_isa_extension_available(const unsigned long
> > *isa_bitmap, int bit)
> > +{
> > +	const unsigned long *bmap = (isa_bitmap) ? isa_bitmap :
> > riscv_isa;
> > +
> > +	if (bit >= RISCV_ISA_EXT_MAX)
> > +		return false;
> > +
> > +	return test_bit(bit, bmap) ? true : false;
> > +}
> > +EXPORT_SYMBOL_GPL(__riscv_isa_extension_available);
> > +
> >  void riscv_fill_hwcap(void)
> >  {
> >  	struct device_node *node;
> >  	const char *isa;
> > -	size_t i;
> > +	char print_str[BITS_PER_LONG+1];
> > +	size_t i, j, isa_len;
> >  	static unsigned long isa2hwcap[256] = {0};
> >  
> >  	isa2hwcap['i'] = isa2hwcap['I'] = COMPAT_HWCAP_ISA_I;
> > @@ -32,8 +75,11 @@ void riscv_fill_hwcap(void)
> >  
> >  	elf_hwcap = 0;
> >  
> > +	bitmap_zero(riscv_isa, RISCV_ISA_EXT_MAX);
> > +
> >  	for_each_of_cpu_node(node) {
> >  		unsigned long this_hwcap = 0;
> > +		unsigned long this_isa = 0;
> >  
> >  		if (riscv_of_processor_hartid(node) < 0)
> >  			continue;
> > @@ -43,8 +89,20 @@ void riscv_fill_hwcap(void)
> >  			continue;
> >  		}
> >  
> > -		for (i = 0; i < strlen(isa); ++i)
> > +		i = 0;
> > +		isa_len = strlen(isa);
> > +#if defined(CONFIG_32BIT)
> > +		if (!strncmp(isa, "rv32", 4))
> > +			i += 4;
> > +#elif defined(CONFIG_64BIT)
> > +		if (!strncmp(isa, "rv64", 4))
> > +			i += 4;
> > +#endif
> > +		for (; i < isa_len; ++i) {
> >  			this_hwcap |= isa2hwcap[(unsigned
> > char)(isa[i])];
> > +			if ('a' <= isa[i] && isa[i] <= 'z')
> > +				this_isa |= (1UL << (isa[i] - 'a'));
> 
> Continuing from the earlier comment, this code won't properly handle
> the X 
> and Z prefix extensions.  So maybe for the time being, we should just
> drop 
> the lines mentioned earlier that imply that we can parse Z-prefix 
> extensions, and change this line so it ignores X and Z letters?
> 
> Then a subsequent patch can add support for more complicated
> extension 
> string parsing.
> 
> 
> > +		}
> >  
> >  		/*
> >  		 * All "okay" hart should have same isa. Set HWCAP
> > based on
> > @@ -55,6 +113,11 @@ void riscv_fill_hwcap(void)
> >  			elf_hwcap &= this_hwcap;
> >  		else
> >  			elf_hwcap = this_hwcap;
> > +
> > +		if (riscv_isa[0])
> > +			riscv_isa[0] &= this_isa;
> > +		else
> > +			riscv_isa[0] = this_isa;
> >  	}
> >  
> >  	/* We don't support systems with F but without D, so mask those
> > out
> > @@ -64,7 +127,17 @@ void riscv_fill_hwcap(void)
> >  		elf_hwcap &= ~COMPAT_HWCAP_ISA_F;
> >  	}
> >  
> > -	pr_info("elf_hwcap is 0x%lx\n", elf_hwcap);
> > +	memset(print_str, 0, sizeof(print_str));
> > +	for (i = 0, j = 0; i < BITS_PER_LONG; i++)
> > +		if (riscv_isa[0] & BIT_MASK(i))
> > +			print_str[j++] = (char)('a' + i);
> > +	pr_info("riscv: ISA extensions %s\n", print_str);
> > +
> > +	memset(print_str, 0, sizeof(print_str));
> > +	for (i = 0, j = 0; i < BITS_PER_LONG; i++)
> > +		if (elf_hwcap & BIT_MASK(i))
> > +			print_str[j++] = (char)('a' + i);
> > +	pr_info("riscv: ELF capabilities %s\n", print_str);
> >  
> >  #ifdef CONFIG_FPU
> >  	if (elf_hwcap & (COMPAT_HWCAP_ISA_F | COMPAT_HWCAP_ISA_D))
> > -- 
> > 2.17.1
> > 
> > 
> 
> - Paul
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[PATCH v7 03/21] RISC-V: Export few kernel symbols

[Anup Patel]

From: Atish Patra <atish.patra@wdc.com>

Export few symbols used by kvm module. Without this, kvm cannot
be compiled as a module.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
 arch/riscv/kernel/smp.c  | 2 +-
 arch/riscv/kernel/time.c | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 5a9834503a2f..402979f575de 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -193,4 +193,4 @@ void smp_send_reschedule(int cpu)
 {
 	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
 }
-
+EXPORT_SYMBOL_GPL(smp_send_reschedule);
diff --git a/arch/riscv/kernel/time.c b/arch/riscv/kernel/time.c
index 541a2b885814..9dd1f2e64db1 100644
--- a/arch/riscv/kernel/time.c
+++ b/arch/riscv/kernel/time.c
@@ -9,6 +9,7 @@
 #include <asm/sbi.h>
 
 unsigned long riscv_timebase;
+EXPORT_SYMBOL_GPL(riscv_timebase);
 
 void __init time_init(void)
 {
-- 
2.17.1


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Re: [PATCH v7 03/21] RISC-V: Export few kernel symbols

[Paul Walmsley]

On Wed, 4 Sep 2019, Anup Patel wrote:

> From: Atish Patra <atish.patra@wdc.com>
> 
> Export few symbols used by kvm module. Without this, kvm cannot
> be compiled as a module.
> 
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> Reviewed-by: Alexander Graf <graf@amazon.com>

Thanks, have updated this patch to apply and to clarify the patch title 
and have queued the following for v5.4-rc.


- Paul

From: Atish Patra <atish.patra@wdc.com>
Date: Wed, 4 Sep 2019 16:14:06 +0000
Subject: [PATCH] RISC-V: Export kernel symbols for kvm

Export few symbols used by kvm module. Without this, kvm cannot
be compiled as a module.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
[paul.walmsley@sifive.com: updated to apply; clarified short patch 
 description]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
---
 arch/riscv/kernel/smp.c  | 1 +
 arch/riscv/kernel/time.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index d70e3c0ee983..f849a2480600 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -210,3 +210,4 @@ void smp_send_reschedule(int cpu)
 {
 	send_ipi_single(cpu, IPI_RESCHEDULE);
 }
+EXPORT_SYMBOL_GPL(smp_send_reschedule);
diff --git a/arch/riscv/kernel/time.c b/arch/riscv/kernel/time.c
index 517d2153a933..8a25d1e440ca 100644
--- a/arch/riscv/kernel/time.c
+++ b/arch/riscv/kernel/time.c
@@ -9,6 +9,7 @@
 #include <asm/processor.h>
 
 unsigned long riscv_timebase;
+EXPORT_SYMBOL_GPL(riscv_timebase);
 
 void __init time_init(void)
 {
-- 
2.23.0


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[PATCH v7 04/21] RISC-V: Add hypervisor extension related CSR defines

[Anup Patel]

This patch extends asm/csr.h by adding RISC-V hypervisor extension
related defines.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
 arch/riscv/include/asm/csr.h | 58 ++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
index a18923fa23c8..059c5cb22aaf 100644
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
@@ -27,6 +27,8 @@
 #define SR_XS_CLEAN	_AC(0x00010000, UL)
 #define SR_XS_DIRTY	_AC(0x00018000, UL)
 
+#define SR_MXR		_AC(0x00080000, UL)
+
 #ifndef CONFIG_64BIT
 #define SR_SD		_AC(0x80000000, UL) /* FS/XS dirty */
 #else
@@ -59,10 +61,13 @@
 
 #define EXC_INST_MISALIGNED	0
 #define EXC_INST_ACCESS		1
+#define EXC_INST_ILLEGAL	2
 #define EXC_BREAKPOINT		3
 #define EXC_LOAD_ACCESS		5
 #define EXC_STORE_ACCESS	7
 #define EXC_SYSCALL		8
+#define EXC_HYPERVISOR_SYSCALL	9
+#define EXC_SUPERVISOR_SYSCALL	10
 #define EXC_INST_PAGE_FAULT	12
 #define EXC_LOAD_PAGE_FAULT	13
 #define EXC_STORE_PAGE_FAULT	15
@@ -72,6 +77,43 @@
 #define SIE_STIE		(_AC(0x1, UL) << IRQ_S_TIMER)
 #define SIE_SEIE		(_AC(0x1, UL) << IRQ_S_EXT)
 
+/* HSTATUS flags */
+#define HSTATUS_VTSR		_AC(0x00400000, UL)
+#define HSTATUS_VTVM		_AC(0x00100000, UL)
+#define HSTATUS_SP2V		_AC(0x00000200, UL)
+#define HSTATUS_SP2P		_AC(0x00000100, UL)
+#define HSTATUS_SPV		_AC(0x00000080, UL)
+#define HSTATUS_STL		_AC(0x00000040, UL)
+#define HSTATUS_SPRV		_AC(0x00000001, UL)
+
+/* HGATP flags */
+#define HGATP_MODE_OFF		_AC(0, UL)
+#define HGATP_MODE_SV32X4	_AC(1, UL)
+#define HGATP_MODE_SV39X4	_AC(8, UL)
+#define HGATP_MODE_SV48X4	_AC(9, UL)
+
+#define HGATP32_MODE_SHIFT	31
+#define HGATP32_VMID_SHIFT	22
+#define HGATP32_VMID_MASK	_AC(0x1FC00000, UL)
+#define HGATP32_PPN		_AC(0x003FFFFF, UL)
+
+#define HGATP64_MODE_SHIFT	60
+#define HGATP64_VMID_SHIFT	44
+#define HGATP64_VMID_MASK	_AC(0x03FFF00000000000, UL)
+#define HGATP64_PPN		_AC(0x00000FFFFFFFFFFF, UL)
+
+#ifdef CONFIG_64BIT
+#define HGATP_PPN		HGATP64_PPN
+#define HGATP_VMID_SHIFT	HGATP64_VMID_SHIFT
+#define HGATP_VMID_MASK		HGATP64_VMID_MASK
+#define HGATP_MODE		(HGATP_MODE_SV39X4 << HGATP64_MODE_SHIFT)
+#else
+#define HGATP_PPN		HGATP32_PPN
+#define HGATP_VMID_SHIFT	HGATP32_VMID_SHIFT
+#define HGATP_VMID_MASK		HGATP32_VMID_MASK
+#define HGATP_MODE		(HGATP_MODE_SV32X4 << HGATP32_MODE_SHIFT)
+#endif
+
 #define CSR_CYCLE		0xc00
 #define CSR_TIME		0xc01
 #define CSR_INSTRET		0xc02
@@ -85,6 +127,22 @@
 #define CSR_STVAL		0x143
 #define CSR_SIP			0x144
 #define CSR_SATP		0x180
+
+#define CSR_VSSTATUS		0x200
+#define CSR_VSIE		0x204
+#define CSR_VSTVEC		0x205
+#define CSR_VSSCRATCH		0x240
+#define CSR_VSEPC		0x241
+#define CSR_VSCAUSE		0x242
+#define CSR_VSTVAL		0x243
+#define CSR_VSIP		0x244
+#define CSR_VSATP		0x280
+
+#define CSR_HSTATUS		0x600
+#define CSR_HEDELEG		0x602
+#define CSR_HIDELEG		0x603
+#define CSR_HGATP		0x680
+
 #define CSR_CYCLEH		0xc80
 #define CSR_TIMEH		0xc81
 #define CSR_INSTRETH		0xc82
-- 
2.17.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v7 05/21] RISC-V: Add initial skeletal KVM support

[Anup Patel]

This patch adds initial skeletal KVM RISC-V support which has:
1. A simple implementation of arch specific VM functions
   except kvm_vm_ioctl_get_dirty_log() which will implemeted
   in-future as part of stage2 page loging.
2. Stubs of required arch specific VCPU functions except
   kvm_arch_vcpu_ioctl_run() which is semi-complete and
   extended by subsequent patches.
3. Stubs for required arch specific stage2 MMU functions.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
 arch/riscv/Kconfig                |   2 +
 arch/riscv/Makefile               |   2 +
 arch/riscv/include/asm/kvm_host.h |  81 ++++++++
 arch/riscv/include/uapi/asm/kvm.h |  47 +++++
 arch/riscv/kvm/Kconfig            |  33 ++++
 arch/riscv/kvm/Makefile           |  13 ++
 arch/riscv/kvm/main.c             |  80 ++++++++
 arch/riscv/kvm/mmu.c              |  83 ++++++++
 arch/riscv/kvm/vcpu.c             | 312 ++++++++++++++++++++++++++++++
 arch/riscv/kvm/vcpu_exit.c        |  35 ++++
 arch/riscv/kvm/vm.c               |  79 ++++++++
 11 files changed, 767 insertions(+)
 create mode 100644 arch/riscv/include/asm/kvm_host.h
 create mode 100644 arch/riscv/include/uapi/asm/kvm.h
 create mode 100644 arch/riscv/kvm/Kconfig
 create mode 100644 arch/riscv/kvm/Makefile
 create mode 100644 arch/riscv/kvm/main.c
 create mode 100644 arch/riscv/kvm/mmu.c
 create mode 100644 arch/riscv/kvm/vcpu.c
 create mode 100644 arch/riscv/kvm/vcpu_exit.c
 create mode 100644 arch/riscv/kvm/vm.c

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 83e48e2fbd4a..9ba340713b8a 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -290,3 +290,5 @@ menu "Power management options"
 source "kernel/power/Kconfig"
 
 endmenu
+
+source "arch/riscv/kvm/Kconfig"
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 7a117be8297c..9f4f418978b1 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -74,6 +74,8 @@ head-y := arch/riscv/kernel/head.o
 
 core-y += arch/riscv/kernel/ arch/riscv/mm/ arch/riscv/net/
 
+core-$(CONFIG_KVM) += arch/riscv/kvm/
+
 libs-y += arch/riscv/lib/
 
 PHONY += vdso_install
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
new file mode 100644
index 000000000000..9459709656be
--- /dev/null
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#ifndef __RISCV_KVM_HOST_H__
+#define __RISCV_KVM_HOST_H__
+
+#include <linux/types.h>
+#include <linux/kvm.h>
+#include <linux/kvm_types.h>
+
+#ifdef CONFIG_64BIT
+#define KVM_MAX_VCPUS			(1U << 16)
+#else
+#define KVM_MAX_VCPUS			(1U << 9)
+#endif
+
+#define KVM_USER_MEM_SLOTS		512
+#define KVM_HALT_POLL_NS_DEFAULT	500000
+
+#define KVM_VCPU_MAX_FEATURES		0
+
+#define KVM_REQ_SLEEP \
+	KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
+#define KVM_REQ_VCPU_RESET		KVM_ARCH_REQ(1)
+
+struct kvm_vm_stat {
+	ulong remote_tlb_flush;
+};
+
+struct kvm_vcpu_stat {
+	u64 halt_successful_poll;
+	u64 halt_attempted_poll;
+	u64 halt_poll_invalid;
+	u64 halt_wakeup;
+	u64 ecall_exit_stat;
+	u64 wfi_exit_stat;
+	u64 mmio_exit_user;
+	u64 mmio_exit_kernel;
+	u64 exits;
+};
+
+struct kvm_arch_memory_slot {
+};
+
+struct kvm_arch {
+	/* stage2 page table */
+	pgd_t *pgd;
+	phys_addr_t pgd_phys;
+};
+
+struct kvm_vcpu_arch {
+	/* Don't run the VCPU (blocked) */
+	bool pause;
+
+	/* SRCU lock index for in-kernel run loop */
+	int srcu_idx;
+};
+
+static inline void kvm_arch_hardware_unsetup(void) {}
+static inline void kvm_arch_sync_events(struct kvm *kvm) {}
+static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
+static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
+static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {}
+
+void kvm_riscv_stage2_flush_cache(struct kvm_vcpu *vcpu);
+int kvm_riscv_stage2_alloc_pgd(struct kvm *kvm);
+void kvm_riscv_stage2_free_pgd(struct kvm *kvm);
+void kvm_riscv_stage2_update_hgatp(struct kvm_vcpu *vcpu);
+
+int kvm_riscv_vcpu_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run);
+int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
+			unsigned long scause, unsigned long stval);
+
+static inline void __kvm_riscv_switch_to(struct kvm_vcpu_arch *vcpu_arch) {}
+
+#endif /* __RISCV_KVM_HOST_H__ */
diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
new file mode 100644
index 000000000000..d15875818b6e
--- /dev/null
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#ifndef __LINUX_KVM_RISCV_H
+#define __LINUX_KVM_RISCV_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+#include <asm/ptrace.h>
+
+#define __KVM_HAVE_READONLY_MEM
+
+#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
+
+/* for KVM_GET_REGS and KVM_SET_REGS */
+struct kvm_regs {
+};
+
+/* for KVM_GET_FPU and KVM_SET_FPU */
+struct kvm_fpu {
+};
+
+/* KVM Debug exit structure */
+struct kvm_debug_exit_arch {
+};
+
+/* for KVM_SET_GUEST_DEBUG */
+struct kvm_guest_debug_arch {
+};
+
+/* definition of registers in kvm_run */
+struct kvm_sync_regs {
+};
+
+/* dummy definition */
+struct kvm_sregs {
+};
+
+#endif
+
+#endif /* __LINUX_KVM_RISCV_H */
diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
new file mode 100644
index 000000000000..35fd30d0e432
--- /dev/null
+++ b/arch/riscv/kvm/Kconfig
@@ -0,0 +1,33 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# KVM configuration
+#
+
+source "virt/kvm/Kconfig"
+
+menuconfig VIRTUALIZATION
+	bool "Virtualization"
+	help
+	  Say Y here to get to see options for using your Linux host to run
+	  other operating systems inside virtual machines (guests).
+	  This option alone does not add any kernel code.
+
+	  If you say N, all options in this submenu will be skipped and
+	  disabled.
+
+if VIRTUALIZATION
+
+config KVM
+	tristate "Kernel-based Virtual Machine (KVM) support"
+	depends on OF
+	select PREEMPT_NOTIFIERS
+	select ANON_INODES
+	select KVM_MMIO
+	select HAVE_KVM_VCPU_ASYNC_IOCTL
+	select SRCU
+	help
+	  Support hosting virtualized guest machines.
+
+	  If unsure, say N.
+
+endif # VIRTUALIZATION
diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
new file mode 100644
index 000000000000..37b5a59d4f4f
--- /dev/null
+++ b/arch/riscv/kvm/Makefile
@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: GPL-2.0
+# Makefile for RISC-V KVM support
+#
+
+common-objs-y = $(addprefix ../../../virt/kvm/, kvm_main.o coalesced_mmio.o)
+
+ccflags-y := -Ivirt/kvm -Iarch/riscv/kvm
+
+kvm-objs := $(common-objs-y)
+
+kvm-objs += main.o vm.o mmu.o vcpu.o vcpu_exit.o
+
+obj-$(CONFIG_KVM)	+= kvm.o
diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c
new file mode 100644
index 000000000000..e1ffe6d42f39
--- /dev/null
+++ b/arch/riscv/kvm/main.c
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/kvm_host.h>
+#include <asm/csr.h>
+#include <asm/hwcap.h>
+
+long kvm_arch_dev_ioctl(struct file *filp,
+			unsigned int ioctl, unsigned long arg)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_check_processor_compat(void)
+{
+	return 0;
+}
+
+int kvm_arch_hardware_setup(void)
+{
+	return 0;
+}
+
+int kvm_arch_hardware_enable(void)
+{
+	unsigned long hideleg, hedeleg;
+
+	hedeleg = 0;
+	hedeleg |= (1UL << EXC_INST_MISALIGNED);
+	hedeleg |= (1UL << EXC_BREAKPOINT);
+	hedeleg |= (1UL << EXC_SYSCALL);
+	hedeleg |= (1UL << EXC_INST_PAGE_FAULT);
+	hedeleg |= (1UL << EXC_LOAD_PAGE_FAULT);
+	hedeleg |= (1UL << EXC_STORE_PAGE_FAULT);
+	csr_write(CSR_HEDELEG, hedeleg);
+
+	hideleg = 0;
+	hideleg |= SIE_SSIE;
+	hideleg |= SIE_STIE;
+	hideleg |= SIE_SEIE;
+	csr_write(CSR_HIDELEG, hideleg);
+
+	return 0;
+}
+
+void kvm_arch_hardware_disable(void)
+{
+	csr_write(CSR_HEDELEG, 0);
+	csr_write(CSR_HIDELEG, 0);
+}
+
+int kvm_arch_init(void *opaque)
+{
+	if (!riscv_isa_extension_available(NULL, h)) {
+		kvm_info("hypervisor extension not available\n");
+		return -ENODEV;
+	}
+
+	kvm_info("hypervisor extension available\n");
+
+	return 0;
+}
+
+void kvm_arch_exit(void)
+{
+}
+
+static int riscv_kvm_init(void)
+{
+	return kvm_init(NULL, sizeof(struct kvm_vcpu), 0, THIS_MODULE);
+}
+module_init(riscv_kvm_init);
diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
new file mode 100644
index 000000000000..04dd089b86ff
--- /dev/null
+++ b/arch/riscv/kvm/mmu.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/hugetlb.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+#include <linux/kvm_host.h>
+#include <linux/sched/signal.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free,
+			   struct kvm_memory_slot *dont)
+{
+}
+
+int kvm_arch_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot,
+			    unsigned long npages)
+{
+	return 0;
+}
+
+void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen)
+{
+}
+
+void kvm_arch_flush_shadow_all(struct kvm *kvm)
+{
+	/* TODO: */
+}
+
+void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
+				   struct kvm_memory_slot *slot)
+{
+}
+
+void kvm_arch_commit_memory_region(struct kvm *kvm,
+				const struct kvm_userspace_memory_region *mem,
+				const struct kvm_memory_slot *old,
+				const struct kvm_memory_slot *new,
+				enum kvm_mr_change change)
+{
+	/* TODO: */
+}
+
+int kvm_arch_prepare_memory_region(struct kvm *kvm,
+				struct kvm_memory_slot *memslot,
+				const struct kvm_userspace_memory_region *mem,
+				enum kvm_mr_change change)
+{
+	/* TODO: */
+	return 0;
+}
+
+void kvm_riscv_stage2_flush_cache(struct kvm_vcpu *vcpu)
+{
+	/* TODO: */
+}
+
+int kvm_riscv_stage2_alloc_pgd(struct kvm *kvm)
+{
+	/* TODO: */
+	return 0;
+}
+
+void kvm_riscv_stage2_free_pgd(struct kvm *kvm)
+{
+	/* TODO: */
+}
+
+void kvm_riscv_stage2_update_hgatp(struct kvm_vcpu *vcpu)
+{
+	/* TODO: */
+}
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
new file mode 100644
index 000000000000..48536cb0c8e7
--- /dev/null
+++ b/arch/riscv/kvm/vcpu.c
@@ -0,0 +1,312 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/kdebug.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+#include <linux/sched/signal.h>
+#include <linux/fs.h>
+#include <linux/kvm_host.h>
+#include <asm/csr.h>
+#include <asm/delay.h>
+#include <asm/hwcap.h>
+
+#define VCPU_STAT(x) { #x, offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU }
+
+struct kvm_stats_debugfs_item debugfs_entries[] = {
+	VCPU_STAT(ecall_exit_stat),
+	VCPU_STAT(wfi_exit_stat),
+	VCPU_STAT(mmio_exit_user),
+	VCPU_STAT(mmio_exit_kernel),
+	VCPU_STAT(exits),
+	{ NULL }
+};
+
+struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
+{
+	/* TODO: */
+	return NULL;
+}
+
+int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
+{
+	return 0;
+}
+
+void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
+{
+}
+
+int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
+{
+	/* TODO: */
+	return 0;
+}
+
+void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
+{
+	/* TODO: */
+}
+
+int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
+{
+	/* TODO: */
+	return 0;
+}
+
+void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu)
+{
+}
+
+void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu)
+{
+}
+
+int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
+{
+	/* TODO: */
+	return 0;
+}
+
+int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
+{
+	/* TODO: */
+	return 0;
+}
+
+bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
+{
+	/* TODO: */
+	return false;
+}
+
+bool kvm_arch_has_vcpu_debugfs(void)
+{
+	return false;
+}
+
+int kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu)
+{
+	return 0;
+}
+
+vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
+{
+	return VM_FAULT_SIGBUS;
+}
+
+long kvm_arch_vcpu_async_ioctl(struct file *filp,
+			       unsigned int ioctl, unsigned long arg)
+{
+	/* TODO; */
+	return -ENOIOCTLCMD;
+}
+
+long kvm_arch_vcpu_ioctl(struct file *filp,
+			 unsigned int ioctl, unsigned long arg)
+{
+	/* TODO: */
+	return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
+				  struct kvm_sregs *sregs)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
+				  struct kvm_sregs *sregs)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
+				  struct kvm_translation *tr)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
+{
+	return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
+				    struct kvm_mp_state *mp_state)
+{
+	/* TODO: */
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
+				    struct kvm_mp_state *mp_state)
+{
+	/* TODO: */
+	return 0;
+}
+
+int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
+					struct kvm_guest_debug *dbg)
+{
+	/* TODO; To be implemented later. */
+	return -EINVAL;
+}
+
+void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
+{
+	/* TODO: */
+
+	kvm_riscv_stage2_update_hgatp(vcpu);
+}
+
+void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
+{
+	/* TODO: */
+}
+
+static void kvm_riscv_check_vcpu_requests(struct kvm_vcpu *vcpu)
+{
+	/* TODO: */
+}
+
+int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	int ret;
+	unsigned long scause, stval;
+
+	vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+
+	/* Process MMIO value returned from user-space */
+	if (run->exit_reason == KVM_EXIT_MMIO) {
+		ret = kvm_riscv_vcpu_mmio_return(vcpu, vcpu->run);
+		if (ret) {
+			srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
+			return ret;
+		}
+	}
+
+	if (run->immediate_exit) {
+		srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
+		return -EINTR;
+	}
+
+	vcpu_load(vcpu);
+
+	kvm_sigset_activate(vcpu);
+
+	ret = 1;
+	run->exit_reason = KVM_EXIT_UNKNOWN;
+	while (ret > 0) {
+		/* Check conditions before entering the guest */
+		cond_resched();
+
+		kvm_riscv_check_vcpu_requests(vcpu);
+
+		preempt_disable();
+
+		local_irq_disable();
+
+		/*
+		 * Exit if we have a signal pending so that we can deliver
+		 * the signal to user space.
+		 */
+		if (signal_pending(current)) {
+			ret = -EINTR;
+			run->exit_reason = KVM_EXIT_INTR;
+		}
+
+		/*
+		 * Ensure we set mode to IN_GUEST_MODE after we disable
+		 * interrupts and before the final VCPU requests check.
+		 * See the comment in kvm_vcpu_exiting_guest_mode() and
+		 * Documentation/virtual/kvm/vcpu-requests.rst
+		 */
+		vcpu->mode = IN_GUEST_MODE;
+
+		srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
+		smp_mb__after_srcu_read_unlock();
+
+		if (ret <= 0 ||
+		    kvm_request_pending(vcpu)) {
+			vcpu->mode = OUTSIDE_GUEST_MODE;
+			local_irq_enable();
+			preempt_enable();
+			vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+			continue;
+		}
+
+		guest_enter_irqoff();
+
+		__kvm_riscv_switch_to(&vcpu->arch);
+
+		vcpu->mode = OUTSIDE_GUEST_MODE;
+		vcpu->stat.exits++;
+
+		/* Save SCAUSE and STVAL because we might get an interrupt
+		 * between __kvm_riscv_switch_to() and local_irq_enable()
+		 * which can potentially overwrite SCAUSE and STVAL.
+		 */
+		scause = csr_read(CSR_SCAUSE);
+		stval = csr_read(CSR_STVAL);
+
+		/*
+		 * We may have taken a host interrupt in VS/VU-mode (i.e.
+		 * while executing the guest). This interrupt is still
+		 * pending, as we haven't serviced it yet!
+		 *
+		 * We're now back in HS-mode with interrupts disabled
+		 * so enabling the interrupts now will have the effect
+		 * of taking the interrupt again, in HS-mode this time.
+		 */
+		local_irq_enable();
+
+		/*
+		 * We do local_irq_enable() before calling guest_exit() so
+		 * that if a timer interrupt hits while running the guest
+		 * we account that tick as being spent in the guest. We
+		 * enable preemption after calling guest_exit() so that if
+		 * we get preempted we make sure ticks after that is not
+		 * counted as guest time.
+		 */
+		guest_exit();
+
+		preempt_enable();
+
+		vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+
+		ret = kvm_riscv_vcpu_exit(vcpu, run, scause, stval);
+	}
+
+	kvm_sigset_deactivate(vcpu);
+
+	vcpu_put(vcpu);
+
+	srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
+
+	return ret;
+}
diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
new file mode 100644
index 000000000000..e4d7c8f0807a
--- /dev/null
+++ b/arch/riscv/kvm/vcpu_exit.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/kvm_host.h>
+
+/**
+ * kvm_riscv_vcpu_mmio_return -- Handle MMIO loads after user space emulation
+ *			     or in-kernel IO emulation
+ *
+ * @vcpu: The VCPU pointer
+ * @run:  The VCPU run struct containing the mmio data
+ */
+int kvm_riscv_vcpu_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+	/* TODO: */
+	return 0;
+}
+
+/*
+ * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
+ * proper exit to userspace.
+ */
+int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
+			unsigned long scause, unsigned long stval)
+{
+	/* TODO: */
+	return 0;
+}
diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c
new file mode 100644
index 000000000000..ac0211820521
--- /dev/null
+++ b/arch/riscv/kvm/vm.c
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <linux/kvm_host.h>
+
+int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
+{
+	/* TODO: To be added later. */
+	return -ENOTSUPP;
+}
+
+int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
+{
+	int r;
+
+	r = kvm_riscv_stage2_alloc_pgd(kvm);
+	if (r)
+		return r;
+
+	return 0;
+}
+
+void kvm_arch_destroy_vm(struct kvm *kvm)
+{
+	int i;
+
+	for (i = 0; i < KVM_MAX_VCPUS; ++i) {
+		if (kvm->vcpus[i]) {
+			kvm_arch_vcpu_destroy(kvm->vcpus[i]);
+			kvm->vcpus[i] = NULL;
+		}
+	}
+}
+
+int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
+{
+	int r;
+
+	switch (ext) {
+	case KVM_CAP_DEVICE_CTRL:
+	case KVM_CAP_USER_MEMORY:
+	case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
+	case KVM_CAP_ONE_REG:
+	case KVM_CAP_READONLY_MEM:
+	case KVM_CAP_MP_STATE:
+	case KVM_CAP_IMMEDIATE_EXIT:
+		r = 1;
+		break;
+	case KVM_CAP_NR_VCPUS:
+		r = num_online_cpus();
+		break;
+	case KVM_CAP_MAX_VCPUS:
+		r = KVM_MAX_VCPUS;
+		break;
+	case KVM_CAP_NR_MEMSLOTS:
+		r = KVM_USER_MEM_SLOTS;
+		break;
+	default:
+		r = 0;
+		break;
+	}
+
+	return r;
+}
+
+long kvm_arch_vm_ioctl(struct file *filp,
+		       unsigned int ioctl, unsigned long arg)
+{
+	return -EINVAL;
+}
-- 
2.17.1


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[PATCH v7 06/21] RISC-V: KVM: Implement VCPU create, init and destroy functions

[Anup Patel]

This patch implements VCPU create, init and destroy functions
required by generic KVM module. We don't have much dynamic
resources in struct kvm_vcpu_arch so thest functions are quite
simple for KVM RISC-V.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
 arch/riscv/include/asm/kvm_host.h | 68 +++++++++++++++++++++++++++++++
 arch/riscv/kvm/vcpu.c             | 68 +++++++++++++++++++++++++++++--
 2 files changed, 132 insertions(+), 4 deletions(-)

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 9459709656be..dab32c9c3470 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -53,7 +53,75 @@ struct kvm_arch {
 	phys_addr_t pgd_phys;
 };
 
+struct kvm_cpu_context {
+	unsigned long zero;
+	unsigned long ra;
+	unsigned long sp;
+	unsigned long gp;
+	unsigned long tp;
+	unsigned long t0;
+	unsigned long t1;
+	unsigned long t2;
+	unsigned long s0;
+	unsigned long s1;
+	unsigned long a0;
+	unsigned long a1;
+	unsigned long a2;
+	unsigned long a3;
+	unsigned long a4;
+	unsigned long a5;
+	unsigned long a6;
+	unsigned long a7;
+	unsigned long s2;
+	unsigned long s3;
+	unsigned long s4;
+	unsigned long s5;
+	unsigned long s6;
+	unsigned long s7;
+	unsigned long s8;
+	unsigned long s9;
+	unsigned long s10;
+	unsigned long s11;
+	unsigned long t3;
+	unsigned long t4;
+	unsigned long t5;
+	unsigned long t6;
+	unsigned long sepc;
+	unsigned long sstatus;
+	unsigned long hstatus;
+};
+
+struct kvm_vcpu_csr {
+	unsigned long vsstatus;
+	unsigned long vsie;
+	unsigned long vstvec;
+	unsigned long vsscratch;
+	unsigned long vsepc;
+	unsigned long vscause;
+	unsigned long vstval;
+	unsigned long vsip;
+	unsigned long vsatp;
+};
+
 struct kvm_vcpu_arch {
+	/* VCPU ran atleast once */
+	bool ran_atleast_once;
+
+	/* ISA feature bits (similar to MISA) */
+	unsigned long isa;
+
+	/* CPU context of Guest VCPU */
+	struct kvm_cpu_context guest_context;
+
+	/* CPU CSR context of Guest VCPU */
+	struct kvm_vcpu_csr guest_csr;
+
+	/* CPU context upon Guest VCPU reset */
+	struct kvm_cpu_context guest_reset_context;
+
+	/* CPU CSR context upon Guest VCPU reset */
+	struct kvm_vcpu_csr guest_reset_csr;
+
 	/* Don't run the VCPU (blocked) */
 	bool pause;
 
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 48536cb0c8e7..8272b05d6ce4 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -31,10 +31,48 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{ NULL }
 };
 
+#define KVM_RISCV_ISA_ALLOWED	(riscv_isa_extension_mask(a) | \
+				 riscv_isa_extension_mask(c) | \
+				 riscv_isa_extension_mask(d) | \
+				 riscv_isa_extension_mask(f) | \
+				 riscv_isa_extension_mask(i) | \
+				 riscv_isa_extension_mask(m) | \
+				 riscv_isa_extension_mask(s) | \
+				 riscv_isa_extension_mask(u))
+
+static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu)
+{
+	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
+	struct kvm_vcpu_csr *reset_csr = &vcpu->arch.guest_reset_csr;
+	struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
+	struct kvm_cpu_context *reset_cntx = &vcpu->arch.guest_reset_context;
+
+	memcpy(csr, reset_csr, sizeof(*csr));
+
+	memcpy(cntx, reset_cntx, sizeof(*cntx));
+}
+
 struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
 {
-	/* TODO: */
-	return NULL;
+	int err;
+	struct kvm_vcpu *vcpu;
+
+	vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
+	if (!vcpu) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	err = kvm_vcpu_init(vcpu, kvm, id);
+	if (err)
+		goto free_vcpu;
+
+	return vcpu;
+
+free_vcpu:
+	kmem_cache_free(kvm_vcpu_cache, vcpu);
+out:
+	return ERR_PTR(err);
 }
 
 int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
@@ -48,13 +86,32 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
 
 int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 {
-	/* TODO: */
+	struct kvm_cpu_context *cntx;
+
+	/* Mark this VCPU never ran */
+	vcpu->arch.ran_atleast_once = false;
+
+	/* Setup ISA features available to VCPU */
+	vcpu->arch.isa = riscv_isa_extension_base(NULL) & KVM_RISCV_ISA_ALLOWED;
+
+	/* Setup reset state of shadow SSTATUS and HSTATUS CSRs */
+	cntx = &vcpu->arch.guest_reset_context;
+	cntx->sstatus = SR_SPP | SR_SPIE;
+	cntx->hstatus = 0;
+	cntx->hstatus |= HSTATUS_SP2V;
+	cntx->hstatus |= HSTATUS_SP2P;
+	cntx->hstatus |= HSTATUS_SPV;
+
+	/* Reset VCPU */
+	kvm_riscv_reset_vcpu(vcpu);
+
 	return 0;
 }
 
 void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 {
-	/* TODO: */
+	kvm_riscv_stage2_flush_cache(vcpu);
+	kmem_cache_free(kvm_vcpu_cache, vcpu);
 }
 
 int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
@@ -199,6 +256,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 	int ret;
 	unsigned long scause, stval;
 
+	/* Mark this VCPU ran atleast once */
+	vcpu->arch.ran_atleast_once = true;
+
 	vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
 
 	/* Process MMIO value returned from user-space */
-- 
2.17.1


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Re: [PATCH v7 06/21] RISC-V: KVM: Implement VCPU create, init and destroy functions

[Alexander Graf]

On 04.09.19 18:14, Anup Patel wrote:
> This patch implements VCPU create, init and destroy functions
> required by generic KVM module. We don't have much dynamic
> resources in struct kvm_vcpu_arch so thest functions are quite

Since you're respinning for v8 anyway, please s/thest/these/ :)

Alex




Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879


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Re: [PATCH v7 06/21] RISC-V: KVM: Implement VCPU create, init and destroy functions

[Anup Patel]

On Mon, Sep 23, 2019 at 12:14 PM Alexander Graf <graf@amazon.com> wrote:
>
>
>
> On 04.09.19 18:14, Anup Patel wrote:
> > This patch implements VCPU create, init and destroy functions
> > required by generic KVM module. We don't have much dynamic
> > resources in struct kvm_vcpu_arch so thest functions are quite
>
> Since you're respinning for v8 anyway, please s/thest/these/ :)

Sure, I will update.

>
> Alex
>
>
>
>
> Amazon Development Center Germany GmbH
> Krausenstr. 38
> 10117 Berlin
> Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
> Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
> Sitz: Berlin
> Ust-ID: DE 289 237 879
>
>

Regards,
Anup

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[PATCH v7 07/21] RISC-V: KVM: Implement VCPU interrupts and requests handling

[Anup Patel]

This patch implements VCPU interrupts and requests which are both
asynchronous events.

The VCPU interrupts can be set/unset using KVM_INTERRUPT ioctl from
user-space. In future, the in-kernel IRQCHIP emulation will use
kvm_riscv_vcpu_set_interrupt() and kvm_riscv_vcpu_unset_interrupt()
functions to set/unset VCPU interrupts.

Important VCPU requests implemented by this patch are:
KVM_REQ_SLEEP       - set whenever VCPU itself goes to sleep state
KVM_REQ_VCPU_RESET  - set whenever VCPU reset is requested

The WFI trap-n-emulate (added later) will use KVM_REQ_SLEEP request
and kvm_riscv_vcpu_has_interrupt() function.

The KVM_REQ_VCPU_RESET request will be used by SBI emulation (added
later) to power-up a VCPU in power-off state. The user-space can use
the GET_MPSTATE/SET_MPSTATE ioctls to get/set power state of a VCPU.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
 arch/riscv/include/asm/kvm_host.h |  26 ++++
 arch/riscv/include/uapi/asm/kvm.h |   3 +
 arch/riscv/kvm/main.c             |   8 ++
 arch/riscv/kvm/vcpu.c             | 193 ++++++++++++++++++++++++++++--
 4 files changed, 217 insertions(+), 13 deletions(-)

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index dab32c9c3470..d801216da6d0 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -122,6 +122,21 @@ struct kvm_vcpu_arch {
 	/* CPU CSR context upon Guest VCPU reset */
 	struct kvm_vcpu_csr guest_reset_csr;
 
+	/*
+	 * VCPU interrupts
+	 *
+	 * We have a lockless approach for tracking pending VCPU interrupts
+	 * implemented using atomic bitops. The irqs_pending bitmap represent
+	 * pending interrupts whereas irqs_pending_mask represent bits changed
+	 * in irqs_pending. Our approach is modeled around multiple producer
+	 * and single consumer problem where the consumer is the VCPU itself.
+	 */
+	unsigned long irqs_pending;
+	unsigned long irqs_pending_mask;
+
+	/* VCPU power-off state */
+	bool power_off;
+
 	/* Don't run the VCPU (blocked) */
 	bool pause;
 
@@ -135,6 +150,9 @@ static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {}
 static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
 static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {}
 
+int kvm_riscv_setup_vsip(void);
+void kvm_riscv_cleanup_vsip(void);
+
 void kvm_riscv_stage2_flush_cache(struct kvm_vcpu *vcpu);
 int kvm_riscv_stage2_alloc_pgd(struct kvm *kvm);
 void kvm_riscv_stage2_free_pgd(struct kvm *kvm);
@@ -146,4 +164,12 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 
 static inline void __kvm_riscv_switch_to(struct kvm_vcpu_arch *vcpu_arch) {}
 
+int kvm_riscv_vcpu_set_interrupt(struct kvm_vcpu *vcpu, unsigned int irq);
+int kvm_riscv_vcpu_unset_interrupt(struct kvm_vcpu *vcpu, unsigned int irq);
+void kvm_riscv_vcpu_flush_interrupts(struct kvm_vcpu *vcpu);
+void kvm_riscv_vcpu_sync_interrupts(struct kvm_vcpu *vcpu);
+bool kvm_riscv_vcpu_has_interrupt(struct kvm_vcpu *vcpu);
+void kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu);
+void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu);
+
 #endif /* __RISCV_KVM_HOST_H__ */
diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
index d15875818b6e..6dbc056d58ba 100644
--- a/arch/riscv/include/uapi/asm/kvm.h
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -18,6 +18,9 @@
 
 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1
 
+#define KVM_INTERRUPT_SET	-1U
+#define KVM_INTERRUPT_UNSET	-2U
+
 /* for KVM_GET_REGS and KVM_SET_REGS */
 struct kvm_regs {
 };
diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c
index e1ffe6d42f39..d088247843c5 100644
--- a/arch/riscv/kvm/main.c
+++ b/arch/riscv/kvm/main.c
@@ -48,6 +48,8 @@ int kvm_arch_hardware_enable(void)
 	hideleg |= SIE_SEIE;
 	csr_write(CSR_HIDELEG, hideleg);
 
+	csr_write(CSR_VSIP, 0);
+
 	return 0;
 }
 
@@ -59,11 +61,17 @@ void kvm_arch_hardware_disable(void)
 
 int kvm_arch_init(void *opaque)
 {
+	int ret;
+
 	if (!riscv_isa_extension_available(NULL, h)) {
 		kvm_info("hypervisor extension not available\n");
 		return -ENODEV;
 	}
 
+	ret = kvm_riscv_setup_vsip();
+	if (ret)
+		return ret;
+
 	kvm_info("hypervisor extension available\n");
 
 	return 0;
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 8272b05d6ce4..3223f723f79e 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -11,6 +11,7 @@
 #include <linux/err.h>
 #include <linux/kdebug.h>
 #include <linux/module.h>
+#include <linux/percpu.h>
 #include <linux/uaccess.h>
 #include <linux/vmalloc.h>
 #include <linux/sched/signal.h>
@@ -40,6 +41,8 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 				 riscv_isa_extension_mask(s) | \
 				 riscv_isa_extension_mask(u))
 
+static unsigned long __percpu *vsip_shadow;
+
 static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu)
 {
 	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
@@ -50,6 +53,9 @@ static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu)
 	memcpy(csr, reset_csr, sizeof(*csr));
 
 	memcpy(cntx, reset_cntx, sizeof(*cntx));
+
+	WRITE_ONCE(vcpu->arch.irqs_pending, 0);
+	WRITE_ONCE(vcpu->arch.irqs_pending_mask, 0);
 }
 
 struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
@@ -116,8 +122,8 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 
 int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
 {
-	/* TODO: */
-	return 0;
+	return READ_ONCE(vcpu->arch.irqs_pending) &
+		vcpu->arch.guest_csr.vsie & (1UL << IRQ_S_TIMER);
 }
 
 void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu)
@@ -130,20 +136,18 @@ void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu)
 
 int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
 {
-	/* TODO: */
-	return 0;
+	return (kvm_riscv_vcpu_has_interrupt(vcpu) &&
+		!vcpu->arch.power_off && !vcpu->arch.pause);
 }
 
 int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
 {
-	/* TODO: */
-	return 0;
+	return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
 }
 
 bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
 {
-	/* TODO: */
-	return false;
+	return (vcpu->arch.guest_context.sstatus & SR_SPP) ? true : false;
 }
 
 bool kvm_arch_has_vcpu_debugfs(void)
@@ -164,7 +168,21 @@ vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
 long kvm_arch_vcpu_async_ioctl(struct file *filp,
 			       unsigned int ioctl, unsigned long arg)
 {
-	/* TODO; */
+	struct kvm_vcpu *vcpu = filp->private_data;
+	void __user *argp = (void __user *)arg;
+
+	if (ioctl == KVM_INTERRUPT) {
+		struct kvm_interrupt irq;
+
+		if (copy_from_user(&irq, argp, sizeof(irq)))
+			return -EFAULT;
+
+		if (irq.irq == KVM_INTERRUPT_SET)
+			return kvm_riscv_vcpu_set_interrupt(vcpu, IRQ_S_EXT);
+		else
+			return kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_S_EXT);
+	}
+
 	return -ENOIOCTLCMD;
 }
 
@@ -213,18 +231,111 @@ int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
 	return -EINVAL;
 }
 
+void kvm_riscv_vcpu_flush_interrupts(struct kvm_vcpu *vcpu)
+{
+	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
+	unsigned long mask, val;
+
+	if (READ_ONCE(vcpu->arch.irqs_pending_mask)) {
+		mask = xchg_acquire(&vcpu->arch.irqs_pending_mask, 0);
+		val = READ_ONCE(vcpu->arch.irqs_pending) & mask;
+
+		csr->vsip &= ~mask;
+		csr->vsip |= val;
+	}
+}
+
+void kvm_riscv_vcpu_sync_interrupts(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.guest_csr.vsip = csr_read(CSR_VSIP);
+	vcpu->arch.guest_csr.vsie = csr_read(CSR_VSIE);
+
+	/* Guest can directly update VSIP software interrupt bits */
+	if (vcpu->arch.guest_csr.vsip ^ READ_ONCE(vcpu->arch.irqs_pending)) {
+		if (vcpu->arch.guest_csr.vsip & (1UL << IRQ_S_SOFT))
+			kvm_riscv_vcpu_set_interrupt(vcpu, IRQ_S_SOFT);
+		else
+			kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_S_SOFT);
+	}
+}
+
+int kvm_riscv_vcpu_set_interrupt(struct kvm_vcpu *vcpu, unsigned int irq)
+{
+	if (irq != IRQ_S_SOFT &&
+	    irq != IRQ_S_TIMER &&
+	    irq != IRQ_S_EXT)
+		return -EINVAL;
+
+	set_bit(irq, &vcpu->arch.irqs_pending);
+	smp_mb__before_atomic();
+	set_bit(irq, &vcpu->arch.irqs_pending_mask);
+
+	kvm_vcpu_kick(vcpu);
+
+	return 0;
+}
+
+int kvm_riscv_vcpu_unset_interrupt(struct kvm_vcpu *vcpu, unsigned int irq)
+{
+	if (irq != IRQ_S_SOFT &&
+	    irq != IRQ_S_TIMER &&
+	    irq != IRQ_S_EXT)
+		return -EINVAL;
+
+	clear_bit(irq, &vcpu->arch.irqs_pending);
+	smp_mb__before_atomic();
+	set_bit(irq, &vcpu->arch.irqs_pending_mask);
+
+	return 0;
+}
+
+bool kvm_riscv_vcpu_has_interrupt(struct kvm_vcpu *vcpu)
+{
+	return (READ_ONCE(vcpu->arch.irqs_pending) &
+		vcpu->arch.guest_csr.vsie) ? true : false;
+}
+
+void kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.power_off = true;
+	kvm_make_request(KVM_REQ_SLEEP, vcpu);
+	kvm_vcpu_kick(vcpu);
+}
+
+void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.power_off = false;
+	kvm_vcpu_wake_up(vcpu);
+}
+
 int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
 				    struct kvm_mp_state *mp_state)
 {
-	/* TODO: */
+	if (vcpu->arch.power_off)
+		mp_state->mp_state = KVM_MP_STATE_STOPPED;
+	else
+		mp_state->mp_state = KVM_MP_STATE_RUNNABLE;
+
 	return 0;
 }
 
 int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
 				    struct kvm_mp_state *mp_state)
 {
-	/* TODO: */
-	return 0;
+	int ret = 0;
+
+	switch (mp_state->mp_state) {
+	case KVM_MP_STATE_RUNNABLE:
+		vcpu->arch.power_off = false;
+		break;
+	case KVM_MP_STATE_STOPPED:
+		kvm_riscv_vcpu_power_off(vcpu);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
 }
 
 int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
@@ -248,7 +359,51 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 
 static void kvm_riscv_check_vcpu_requests(struct kvm_vcpu *vcpu)
 {
-	/* TODO: */
+	struct swait_queue_head *wq = kvm_arch_vcpu_wq(vcpu);
+
+	if (kvm_request_pending(vcpu)) {
+		if (kvm_check_request(KVM_REQ_SLEEP, vcpu)) {
+			swait_event_interruptible_exclusive(*wq,
+						((!vcpu->arch.power_off) &&
+						(!vcpu->arch.pause)));
+
+			if (vcpu->arch.power_off || vcpu->arch.pause) {
+				/*
+				 * Awaken to handle a signal, request to
+				 * sleep again later.
+				 */
+				kvm_make_request(KVM_REQ_SLEEP, vcpu);
+			}
+		}
+
+		if (kvm_check_request(KVM_REQ_VCPU_RESET, vcpu))
+			kvm_riscv_reset_vcpu(vcpu);
+	}
+}
+
+static void kvm_riscv_update_vsip(struct kvm_vcpu *vcpu)
+{
+	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
+	unsigned long *vsip = raw_cpu_ptr(vsip_shadow);
+
+	if (*vsip != csr->vsip) {
+		csr_write(CSR_VSIP, csr->vsip);
+		*vsip = csr->vsip;
+	}
+}
+
+int kvm_riscv_setup_vsip(void)
+{
+	vsip_shadow = alloc_percpu(unsigned long);
+	if (!vsip_shadow)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void kvm_riscv_cleanup_vsip(void)
+{
+	free_percpu(vsip_shadow);
 }
 
 int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
@@ -311,6 +466,15 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
 		smp_mb__after_srcu_read_unlock();
 
+		/*
+		 * We might have got VCPU interrupts updated asynchronously
+		 * so update it in HW.
+		 */
+		kvm_riscv_vcpu_flush_interrupts(vcpu);
+
+		/* Update VSIP CSR for current CPU */
+		kvm_riscv_update_vsip(vcpu);
+
 		if (ret <= 0 ||
 		    kvm_request_pending(vcpu)) {
 			vcpu->mode = OUTSIDE_GUEST_MODE;
@@ -334,6 +498,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		scause = csr_read(CSR_SCAUSE);
 		stval = csr_read(CSR_STVAL);
 
+		/* Syncup interrupts state with HW */
+		kvm_riscv_vcpu_sync_interrupts(vcpu);
+
 		/*
 		 * We may have taken a host interrupt in VS/VU-mode (i.e.
 		 * while executing the guest). This interrupt is still
-- 
2.17.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v7 08/21] RISC-V: KVM: Implement KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctls

[Anup Patel]

For KVM RISC-V, we use KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctls to access
VCPU config and registers from user-space.

We have three types of VCPU registers:
1. CONFIG - these are VCPU config and capabilities
2. CORE   - these are VCPU general purpose registers
3. CSR    - these are VCPU control and status registers

The CONFIG registers available to user-space are ISA and TIMEBASE. Out
of these, TIMEBASE is a read-only register which inform user-space about
VCPU timer base frequency. The ISA register is a read and write register
where user-space can only write the desired VCPU ISA capabilities before
running the VCPU.

The CORE registers available to user-space are PC, RA, SP, GP, TP, A0-A7,
T0-T6, S0-S11 and MODE. Most of these are RISC-V general registers except
PC and MODE. The PC register represents program counter whereas the MODE
register represent VCPU privilege mode (i.e. S/U-mode).

The CSRs available to user-space are SSTATUS, SIE, STVEC, SSCRATCH, SEPC,
SCAUSE, STVAL, SIP, and SATP. All of these are read/write registers.

In future, more VCPU register types will be added (such as FP) for the
KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctls.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/riscv/include/uapi/asm/kvm.h |  46 +++++-
 arch/riscv/kvm/vcpu.c             | 235 +++++++++++++++++++++++++++++-
 2 files changed, 278 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
index 6dbc056d58ba..08c4515ad71b 100644
--- a/arch/riscv/include/uapi/asm/kvm.h
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -23,8 +23,15 @@
 
 /* for KVM_GET_REGS and KVM_SET_REGS */
 struct kvm_regs {
+	/* out (KVM_GET_REGS) / in (KVM_SET_REGS) */
+	struct user_regs_struct regs;
+	unsigned long mode;
 };
 
+/* Possible privilege modes for kvm_regs */
+#define KVM_RISCV_MODE_S	1
+#define KVM_RISCV_MODE_U	0
+
 /* for KVM_GET_FPU and KVM_SET_FPU */
 struct kvm_fpu {
 };
@@ -41,10 +48,47 @@ struct kvm_guest_debug_arch {
 struct kvm_sync_regs {
 };
 
-/* dummy definition */
+/* for KVM_GET_SREGS and KVM_SET_SREGS */
 struct kvm_sregs {
+	unsigned long sstatus;
+	unsigned long sie;
+	unsigned long stvec;
+	unsigned long sscratch;
+	unsigned long sepc;
+	unsigned long scause;
+	unsigned long stval;
+	unsigned long sip;
+	unsigned long satp;
+};
+
+/* for KVM_GET_ONE_REG and KVM_SET_ONE_REG */
+struct kvm_riscv_config {
+	unsigned long isa;
+	unsigned long tbfreq;
 };
 
+#define KVM_REG_SIZE(id)		\
+	(1U << (((id) & KVM_REG_SIZE_MASK) >> KVM_REG_SIZE_SHIFT))
+
+/* If you need to interpret the index values, here is the key: */
+#define KVM_REG_RISCV_TYPE_MASK		0x00000000FF000000
+#define KVM_REG_RISCV_TYPE_SHIFT	24
+
+/* Config registers are mapped as type 1 */
+#define KVM_REG_RISCV_CONFIG		(0x01 << KVM_REG_RISCV_TYPE_SHIFT)
+#define KVM_REG_RISCV_CONFIG_REG(name)	\
+	(offsetof(struct kvm_riscv_config, name) / sizeof(unsigned long))
+
+/* Core registers are mapped as type 2 */
+#define KVM_REG_RISCV_CORE		(0x02 << KVM_REG_RISCV_TYPE_SHIFT)
+#define KVM_REG_RISCV_CORE_REG(name)	\
+		(offsetof(struct kvm_regs, name) / sizeof(unsigned long))
+
+/* Control and status registers are mapped as type 3 */
+#define KVM_REG_RISCV_CSR		(0x03 << KVM_REG_RISCV_TYPE_SHIFT)
+#define KVM_REG_RISCV_CSR_REG(name)	\
+		(offsetof(struct kvm_sregs, name) / sizeof(unsigned long))
+
 #endif
 
 #endif /* __LINUX_KVM_RISCV_H */
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 3223f723f79e..b95dfc959009 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -165,6 +165,215 @@ vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
 	return VM_FAULT_SIGBUS;
 }
 
+static int kvm_riscv_vcpu_get_reg_config(struct kvm_vcpu *vcpu,
+					 const struct kvm_one_reg *reg)
+{
+	unsigned long __user *uaddr =
+			(unsigned long __user *)(unsigned long)reg->addr;
+	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
+					    KVM_REG_SIZE_MASK |
+					    KVM_REG_RISCV_CONFIG);
+	unsigned long reg_val;
+
+	if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
+		return -EINVAL;
+
+	switch (reg_num) {
+	case KVM_REG_RISCV_CONFIG_REG(isa):
+		reg_val = vcpu->arch.isa;
+		break;
+	case KVM_REG_RISCV_CONFIG_REG(tbfreq):
+		reg_val = riscv_timebase;
+		break;
+	default:
+		return -EINVAL;
+	};
+
+	if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int kvm_riscv_vcpu_set_reg_config(struct kvm_vcpu *vcpu,
+					 const struct kvm_one_reg *reg)
+{
+	unsigned long __user *uaddr =
+			(unsigned long __user *)(unsigned long)reg->addr;
+	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
+					    KVM_REG_SIZE_MASK |
+					    KVM_REG_RISCV_CONFIG);
+	unsigned long reg_val;
+
+	if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
+		return -EINVAL;
+
+	if (copy_from_user(&reg_val, uaddr, KVM_REG_SIZE(reg->id)))
+		return -EFAULT;
+
+	switch (reg_num) {
+	case KVM_REG_RISCV_CONFIG_REG(isa):
+		if (!vcpu->arch.ran_atleast_once) {
+			vcpu->arch.isa = reg_val;
+			vcpu->arch.isa &= riscv_isa_extension_base(NULL);
+			vcpu->arch.isa &= KVM_RISCV_ISA_ALLOWED;
+		} else {
+			return -ENOTSUPP;
+		}
+		break;
+	case KVM_REG_RISCV_CONFIG_REG(tbfreq):
+		return -ENOTSUPP;
+	default:
+		return -EINVAL;
+	};
+
+	return 0;
+}
+
+static int kvm_riscv_vcpu_get_reg_core(struct kvm_vcpu *vcpu,
+				       const struct kvm_one_reg *reg)
+{
+	struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
+	unsigned long __user *uaddr =
+			(unsigned long __user *)(unsigned long)reg->addr;
+	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
+					    KVM_REG_SIZE_MASK |
+					    KVM_REG_RISCV_CORE);
+	unsigned long reg_val;
+
+	if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
+		return -EINVAL;
+
+	if (reg_num == KVM_REG_RISCV_CORE_REG(regs.pc))
+		reg_val = cntx->sepc;
+	else if (KVM_REG_RISCV_CORE_REG(regs.pc) < reg_num &&
+		 reg_num <= KVM_REG_RISCV_CORE_REG(regs.t6))
+		reg_val = ((unsigned long *)cntx)[reg_num];
+	else if (reg_num == KVM_REG_RISCV_CORE_REG(mode))
+		reg_val = (cntx->sstatus & SR_SPP) ?
+				KVM_RISCV_MODE_S : KVM_RISCV_MODE_U;
+	else
+		return -EINVAL;
+
+	if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int kvm_riscv_vcpu_set_reg_core(struct kvm_vcpu *vcpu,
+				       const struct kvm_one_reg *reg)
+{
+	struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
+	unsigned long __user *uaddr =
+			(unsigned long __user *)(unsigned long)reg->addr;
+	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
+					    KVM_REG_SIZE_MASK |
+					    KVM_REG_RISCV_CORE);
+	unsigned long reg_val;
+
+	if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
+		return -EINVAL;
+
+	if (copy_from_user(&reg_val, uaddr, KVM_REG_SIZE(reg->id)))
+		return -EFAULT;
+
+	if (reg_num == KVM_REG_RISCV_CORE_REG(regs.pc))
+		cntx->sepc = reg_val;
+	else if (KVM_REG_RISCV_CORE_REG(regs.pc) < reg_num &&
+		 reg_num <= KVM_REG_RISCV_CORE_REG(regs.t6))
+		((unsigned long *)cntx)[reg_num] = reg_val;
+	else if (reg_num == KVM_REG_RISCV_CORE_REG(mode)) {
+		if (reg_val == KVM_RISCV_MODE_S)
+			cntx->sstatus |= SR_SPP;
+		else
+			cntx->sstatus &= ~SR_SPP;
+	} else
+		return -EINVAL;
+
+	return 0;
+}
+
+static int kvm_riscv_vcpu_get_reg_csr(struct kvm_vcpu *vcpu,
+				      const struct kvm_one_reg *reg)
+{
+	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
+	unsigned long __user *uaddr =
+			(unsigned long __user *)(unsigned long)reg->addr;
+	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
+					    KVM_REG_SIZE_MASK |
+					    KVM_REG_RISCV_CSR);
+	unsigned long reg_val;
+
+	if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
+		return -EINVAL;
+	if (reg_num >= sizeof(struct kvm_sregs) / sizeof(unsigned long))
+		return -EINVAL;
+
+	if (reg_num == KVM_REG_RISCV_CSR_REG(sip))
+		kvm_riscv_vcpu_flush_interrupts(vcpu);
+
+	reg_val = ((unsigned long *)csr)[reg_num];
+
+	if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int kvm_riscv_vcpu_set_reg_csr(struct kvm_vcpu *vcpu,
+				      const struct kvm_one_reg *reg)
+{
+	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
+	unsigned long __user *uaddr =
+			(unsigned long __user *)(unsigned long)reg->addr;
+	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
+					    KVM_REG_SIZE_MASK |
+					    KVM_REG_RISCV_CSR);
+	unsigned long reg_val;
+
+	if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
+		return -EINVAL;
+	if (reg_num >= sizeof(struct kvm_sregs) / sizeof(unsigned long))
+		return -EINVAL;
+
+	if (copy_from_user(&reg_val, uaddr, KVM_REG_SIZE(reg->id)))
+		return -EFAULT;
+
+	((unsigned long *)csr)[reg_num] = reg_val;
+
+	if (reg_num == KVM_REG_RISCV_CSR_REG(sip))
+		WRITE_ONCE(vcpu->arch.irqs_pending_mask, 0);
+
+	return 0;
+}
+
+static int kvm_riscv_vcpu_set_reg(struct kvm_vcpu *vcpu,
+				  const struct kvm_one_reg *reg)
+{
+	if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CONFIG)
+		return kvm_riscv_vcpu_set_reg_config(vcpu, reg);
+	else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CORE)
+		return kvm_riscv_vcpu_set_reg_core(vcpu, reg);
+	else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CSR)
+		return kvm_riscv_vcpu_set_reg_csr(vcpu, reg);
+
+	return -EINVAL;
+}
+
+static int kvm_riscv_vcpu_get_reg(struct kvm_vcpu *vcpu,
+				  const struct kvm_one_reg *reg)
+{
+	if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CONFIG)
+		return kvm_riscv_vcpu_get_reg_config(vcpu, reg);
+	else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CORE)
+		return kvm_riscv_vcpu_get_reg_core(vcpu, reg);
+	else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CSR)
+		return kvm_riscv_vcpu_get_reg_csr(vcpu, reg);
+
+	return -EINVAL;
+}
+
 long kvm_arch_vcpu_async_ioctl(struct file *filp,
 			       unsigned int ioctl, unsigned long arg)
 {
@@ -189,8 +398,30 @@ long kvm_arch_vcpu_async_ioctl(struct file *filp,
 long kvm_arch_vcpu_ioctl(struct file *filp,
 			 unsigned int ioctl, unsigned long arg)
 {
-	/* TODO: */
-	return -EINVAL;
+	struct kvm_vcpu *vcpu = filp->private_data;
+	void __user *argp = (void __user *)arg;
+	long r = -EINVAL;
+
+	switch (ioctl) {
+	case KVM_SET_ONE_REG:
+	case KVM_GET_ONE_REG: {
+		struct kvm_one_reg reg;
+
+		r = -EFAULT;
+		if (copy_from_user(&reg, argp, sizeof(reg)))
+			break;
+
+		if (ioctl == KVM_SET_ONE_REG)
+			r = kvm_riscv_vcpu_set_reg(vcpu, &reg);
+		else
+			r = kvm_riscv_vcpu_get_reg(vcpu, &reg);
+		break;
+	}
+	default:
+		break;
+	}
+
+	return r;
 }
 
 int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
-- 
2.17.1


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Re: [PATCH v7 08/21] RISC-V: KVM: Implement KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctls

[Anup Patel]

On Wed, Sep 4, 2019 at 9:44 PM Anup Patel <Anup.Patel@wdc.com> wrote:
>
> For KVM RISC-V, we use KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctls to access
> VCPU config and registers from user-space.
>
> We have three types of VCPU registers:
> 1. CONFIG - these are VCPU config and capabilities
> 2. CORE   - these are VCPU general purpose registers
> 3. CSR    - these are VCPU control and status registers
>
> The CONFIG registers available to user-space are ISA and TIMEBASE. Out
> of these, TIMEBASE is a read-only register which inform user-space about
> VCPU timer base frequency. The ISA register is a read and write register
> where user-space can only write the desired VCPU ISA capabilities before
> running the VCPU.
>
> The CORE registers available to user-space are PC, RA, SP, GP, TP, A0-A7,
> T0-T6, S0-S11 and MODE. Most of these are RISC-V general registers except
> PC and MODE. The PC register represents program counter whereas the MODE
> register represent VCPU privilege mode (i.e. S/U-mode).
>
> The CSRs available to user-space are SSTATUS, SIE, STVEC, SSCRATCH, SEPC,
> SCAUSE, STVAL, SIP, and SATP. All of these are read/write registers.
>
> In future, more VCPU register types will be added (such as FP) for the
> KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctls.
>
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  arch/riscv/include/uapi/asm/kvm.h |  46 +++++-
>  arch/riscv/kvm/vcpu.c             | 235 +++++++++++++++++++++++++++++-
>  2 files changed, 278 insertions(+), 3 deletions(-)
>
> diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
> index 6dbc056d58ba..08c4515ad71b 100644
> --- a/arch/riscv/include/uapi/asm/kvm.h
> +++ b/arch/riscv/include/uapi/asm/kvm.h
> @@ -23,8 +23,15 @@
>
>  /* for KVM_GET_REGS and KVM_SET_REGS */
>  struct kvm_regs {
> +       /* out (KVM_GET_REGS) / in (KVM_SET_REGS) */
> +       struct user_regs_struct regs;
> +       unsigned long mode;
>  };

As discussed in LPC 2019 with Alex Graf, I will add separate
struct for CORE registers instead of re-using "struct kvm_regs".

>
> +/* Possible privilege modes for kvm_regs */
> +#define KVM_RISCV_MODE_S       1
> +#define KVM_RISCV_MODE_U       0
> +
>  /* for KVM_GET_FPU and KVM_SET_FPU */
>  struct kvm_fpu {
>  };
> @@ -41,10 +48,47 @@ struct kvm_guest_debug_arch {
>  struct kvm_sync_regs {
>  };
>
> -/* dummy definition */
> +/* for KVM_GET_SREGS and KVM_SET_SREGS */
>  struct kvm_sregs {
> +       unsigned long sstatus;
> +       unsigned long sie;
> +       unsigned long stvec;
> +       unsigned long sscratch;
> +       unsigned long sepc;
> +       unsigned long scause;
> +       unsigned long stval;
> +       unsigned long sip;
> +       unsigned long satp;
> +};

Same as above, I will add separate struct for CSR registers instead
of re-using "struct kvm_sregs".

> +
> +/* for KVM_GET_ONE_REG and KVM_SET_ONE_REG */
> +struct kvm_riscv_config {
> +       unsigned long isa;
> +       unsigned long tbfreq;
>  };
>
> +#define KVM_REG_SIZE(id)               \
> +       (1U << (((id) & KVM_REG_SIZE_MASK) >> KVM_REG_SIZE_SHIFT))
> +
> +/* If you need to interpret the index values, here is the key: */
> +#define KVM_REG_RISCV_TYPE_MASK                0x00000000FF000000
> +#define KVM_REG_RISCV_TYPE_SHIFT       24
> +
> +/* Config registers are mapped as type 1 */
> +#define KVM_REG_RISCV_CONFIG           (0x01 << KVM_REG_RISCV_TYPE_SHIFT)
> +#define KVM_REG_RISCV_CONFIG_REG(name) \
> +       (offsetof(struct kvm_riscv_config, name) / sizeof(unsigned long))
> +
> +/* Core registers are mapped as type 2 */
> +#define KVM_REG_RISCV_CORE             (0x02 << KVM_REG_RISCV_TYPE_SHIFT)
> +#define KVM_REG_RISCV_CORE_REG(name)   \
> +               (offsetof(struct kvm_regs, name) / sizeof(unsigned long))
> +
> +/* Control and status registers are mapped as type 3 */
> +#define KVM_REG_RISCV_CSR              (0x03 << KVM_REG_RISCV_TYPE_SHIFT)
> +#define KVM_REG_RISCV_CSR_REG(name)    \
> +               (offsetof(struct kvm_sregs, name) / sizeof(unsigned long))
> +
>  #endif
>
>  #endif /* __LINUX_KVM_RISCV_H */
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> index 3223f723f79e..b95dfc959009 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -165,6 +165,215 @@ vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
>         return VM_FAULT_SIGBUS;
>  }
>
> +static int kvm_riscv_vcpu_get_reg_config(struct kvm_vcpu *vcpu,
> +                                        const struct kvm_one_reg *reg)
> +{
> +       unsigned long __user *uaddr =
> +                       (unsigned long __user *)(unsigned long)reg->addr;
> +       unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
> +                                           KVM_REG_SIZE_MASK |
> +                                           KVM_REG_RISCV_CONFIG);
> +       unsigned long reg_val;
> +
> +       if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
> +               return -EINVAL;
> +
> +       switch (reg_num) {
> +       case KVM_REG_RISCV_CONFIG_REG(isa):
> +               reg_val = vcpu->arch.isa;
> +               break;
> +       case KVM_REG_RISCV_CONFIG_REG(tbfreq):
> +               reg_val = riscv_timebase;
> +               break;
> +       default:
> +               return -EINVAL;
> +       };
> +
> +       if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
> +               return -EFAULT;
> +
> +       return 0;
> +}
> +
> +static int kvm_riscv_vcpu_set_reg_config(struct kvm_vcpu *vcpu,
> +                                        const struct kvm_one_reg *reg)
> +{
> +       unsigned long __user *uaddr =
> +                       (unsigned long __user *)(unsigned long)reg->addr;
> +       unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
> +                                           KVM_REG_SIZE_MASK |
> +                                           KVM_REG_RISCV_CONFIG);
> +       unsigned long reg_val;
> +
> +       if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
> +               return -EINVAL;
> +
> +       if (copy_from_user(&reg_val, uaddr, KVM_REG_SIZE(reg->id)))
> +               return -EFAULT;
> +
> +       switch (reg_num) {
> +       case KVM_REG_RISCV_CONFIG_REG(isa):
> +               if (!vcpu->arch.ran_atleast_once) {
> +                       vcpu->arch.isa = reg_val;
> +                       vcpu->arch.isa &= riscv_isa_extension_base(NULL);
> +                       vcpu->arch.isa &= KVM_RISCV_ISA_ALLOWED;
> +               } else {
> +                       return -ENOTSUPP;
> +               }
> +               break;
> +       case KVM_REG_RISCV_CONFIG_REG(tbfreq):
> +               return -ENOTSUPP;
> +       default:
> +               return -EINVAL;
> +       };
> +
> +       return 0;
> +}
> +
> +static int kvm_riscv_vcpu_get_reg_core(struct kvm_vcpu *vcpu,
> +                                      const struct kvm_one_reg *reg)
> +{
> +       struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
> +       unsigned long __user *uaddr =
> +                       (unsigned long __user *)(unsigned long)reg->addr;
> +       unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
> +                                           KVM_REG_SIZE_MASK |
> +                                           KVM_REG_RISCV_CORE);
> +       unsigned long reg_val;
> +
> +       if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
> +               return -EINVAL;
> +
> +       if (reg_num == KVM_REG_RISCV_CORE_REG(regs.pc))
> +               reg_val = cntx->sepc;
> +       else if (KVM_REG_RISCV_CORE_REG(regs.pc) < reg_num &&
> +                reg_num <= KVM_REG_RISCV_CORE_REG(regs.t6))
> +               reg_val = ((unsigned long *)cntx)[reg_num];
> +       else if (reg_num == KVM_REG_RISCV_CORE_REG(mode))
> +               reg_val = (cntx->sstatus & SR_SPP) ?
> +                               KVM_RISCV_MODE_S : KVM_RISCV_MODE_U;
> +       else
> +               return -EINVAL;
> +
> +       if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
> +               return -EFAULT;
> +
> +       return 0;
> +}
> +
> +static int kvm_riscv_vcpu_set_reg_core(struct kvm_vcpu *vcpu,
> +                                      const struct kvm_one_reg *reg)
> +{
> +       struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
> +       unsigned long __user *uaddr =
> +                       (unsigned long __user *)(unsigned long)reg->addr;
> +       unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
> +                                           KVM_REG_SIZE_MASK |
> +                                           KVM_REG_RISCV_CORE);
> +       unsigned long reg_val;
> +
> +       if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
> +               return -EINVAL;
> +
> +       if (copy_from_user(&reg_val, uaddr, KVM_REG_SIZE(reg->id)))
> +               return -EFAULT;
> +
> +       if (reg_num == KVM_REG_RISCV_CORE_REG(regs.pc))
> +               cntx->sepc = reg_val;
> +       else if (KVM_REG_RISCV_CORE_REG(regs.pc) < reg_num &&
> +                reg_num <= KVM_REG_RISCV_CORE_REG(regs.t6))
> +               ((unsigned long *)cntx)[reg_num] = reg_val;
> +       else if (reg_num == KVM_REG_RISCV_CORE_REG(mode)) {
> +               if (reg_val == KVM_RISCV_MODE_S)
> +                       cntx->sstatus |= SR_SPP;
> +               else
> +                       cntx->sstatus &= ~SR_SPP;
> +       } else
> +               return -EINVAL;
> +
> +       return 0;
> +}
> +
> +static int kvm_riscv_vcpu_get_reg_csr(struct kvm_vcpu *vcpu,
> +                                     const struct kvm_one_reg *reg)
> +{
> +       struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
> +       unsigned long __user *uaddr =
> +                       (unsigned long __user *)(unsigned long)reg->addr;
> +       unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
> +                                           KVM_REG_SIZE_MASK |
> +                                           KVM_REG_RISCV_CSR);
> +       unsigned long reg_val;
> +
> +       if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
> +               return -EINVAL;
> +       if (reg_num >= sizeof(struct kvm_sregs) / sizeof(unsigned long))
> +               return -EINVAL;
> +
> +       if (reg_num == KVM_REG_RISCV_CSR_REG(sip))
> +               kvm_riscv_vcpu_flush_interrupts(vcpu);
> +
> +       reg_val = ((unsigned long *)csr)[reg_num];
> +
> +       if (copy_to_user(uaddr, &reg_val, KVM_REG_SIZE(reg->id)))
> +               return -EFAULT;
> +
> +       return 0;
> +}
> +
> +static int kvm_riscv_vcpu_set_reg_csr(struct kvm_vcpu *vcpu,
> +                                     const struct kvm_one_reg *reg)
> +{
> +       struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
> +       unsigned long __user *uaddr =
> +                       (unsigned long __user *)(unsigned long)reg->addr;
> +       unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
> +                                           KVM_REG_SIZE_MASK |
> +                                           KVM_REG_RISCV_CSR);
> +       unsigned long reg_val;
> +
> +       if (KVM_REG_SIZE(reg->id) != sizeof(unsigned long))
> +               return -EINVAL;
> +       if (reg_num >= sizeof(struct kvm_sregs) / sizeof(unsigned long))
> +               return -EINVAL;
> +
> +       if (copy_from_user(&reg_val, uaddr, KVM_REG_SIZE(reg->id)))
> +               return -EFAULT;
> +
> +       ((unsigned long *)csr)[reg_num] = reg_val;
> +
> +       if (reg_num == KVM_REG_RISCV_CSR_REG(sip))
> +               WRITE_ONCE(vcpu->arch.irqs_pending_mask, 0);
> +
> +       return 0;
> +}
> +
> +static int kvm_riscv_vcpu_set_reg(struct kvm_vcpu *vcpu,
> +                                 const struct kvm_one_reg *reg)
> +{
> +       if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CONFIG)
> +               return kvm_riscv_vcpu_set_reg_config(vcpu, reg);
> +       else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CORE)
> +               return kvm_riscv_vcpu_set_reg_core(vcpu, reg);
> +       else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CSR)
> +               return kvm_riscv_vcpu_set_reg_csr(vcpu, reg);
> +
> +       return -EINVAL;
> +}
> +
> +static int kvm_riscv_vcpu_get_reg(struct kvm_vcpu *vcpu,
> +                                 const struct kvm_one_reg *reg)
> +{
> +       if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CONFIG)
> +               return kvm_riscv_vcpu_get_reg_config(vcpu, reg);
> +       else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CORE)
> +               return kvm_riscv_vcpu_get_reg_core(vcpu, reg);
> +       else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CSR)
> +               return kvm_riscv_vcpu_get_reg_csr(vcpu, reg);
> +
> +       return -EINVAL;
> +}
> +
>  long kvm_arch_vcpu_async_ioctl(struct file *filp,
>                                unsigned int ioctl, unsigned long arg)
>  {
> @@ -189,8 +398,30 @@ long kvm_arch_vcpu_async_ioctl(struct file *filp,
>  long kvm_arch_vcpu_ioctl(struct file *filp,
>                          unsigned int ioctl, unsigned long arg)
>  {
> -       /* TODO: */
> -       return -EINVAL;
> +       struct kvm_vcpu *vcpu = filp->private_data;
> +       void __user *argp = (void __user *)arg;
> +       long r = -EINVAL;
> +
> +       switch (ioctl) {
> +       case KVM_SET_ONE_REG:
> +       case KVM_GET_ONE_REG: {
> +               struct kvm_one_reg reg;
> +
> +               r = -EFAULT;
> +               if (copy_from_user(&reg, argp, sizeof(reg)))
> +                       break;
> +
> +               if (ioctl == KVM_SET_ONE_REG)
> +                       r = kvm_riscv_vcpu_set_reg(vcpu, &reg);
> +               else
> +                       r = kvm_riscv_vcpu_get_reg(vcpu, &reg);
> +               break;
> +       }
> +       default:
> +               break;
> +       }
> +
> +       return r;
>  }
>
>  int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
> --
> 2.17.1
>

Regards,
Anup

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[PATCH v7 09/21] RISC-V: KVM: Implement VCPU world-switch

[Anup Patel]

This patch implements the VCPU world-switch for KVM RISC-V.

The KVM RISC-V world-switch (i.e. __kvm_riscv_switch_to()) mostly
switches general purpose registers, SSTATUS, STVEC, SSCRATCH and
HSTATUS CSRs. Other CSRs are switched via vcpu_load() and vcpu_put()
interface in kvm_arch_vcpu_load() and kvm_arch_vcpu_put() functions
respectively.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
 arch/riscv/include/asm/kvm_host.h |   9 +-
 arch/riscv/kernel/asm-offsets.c   |  76 ++++++++++++
 arch/riscv/kvm/Makefile           |   2 +-
 arch/riscv/kvm/vcpu.c             |  32 ++++-
 arch/riscv/kvm/vcpu_switch.S      | 194 ++++++++++++++++++++++++++++++
 5 files changed, 309 insertions(+), 4 deletions(-)
 create mode 100644 arch/riscv/kvm/vcpu_switch.S

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index d801216da6d0..18f1097f1d8d 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -110,6 +110,13 @@ struct kvm_vcpu_arch {
 	/* ISA feature bits (similar to MISA) */
 	unsigned long isa;
 
+	/* SSCRATCH and STVEC of Host */
+	unsigned long host_sscratch;
+	unsigned long host_stvec;
+
+	/* CPU context of Host */
+	struct kvm_cpu_context host_context;
+
 	/* CPU context of Guest VCPU */
 	struct kvm_cpu_context guest_context;
 
@@ -162,7 +169,7 @@ int kvm_riscv_vcpu_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run);
 int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 			unsigned long scause, unsigned long stval);
 
-static inline void __kvm_riscv_switch_to(struct kvm_vcpu_arch *vcpu_arch) {}
+void __kvm_riscv_switch_to(struct kvm_vcpu_arch *vcpu_arch);
 
 int kvm_riscv_vcpu_set_interrupt(struct kvm_vcpu *vcpu, unsigned int irq);
 int kvm_riscv_vcpu_unset_interrupt(struct kvm_vcpu *vcpu, unsigned int irq);
diff --git a/arch/riscv/kernel/asm-offsets.c b/arch/riscv/kernel/asm-offsets.c
index 9f5628c38ac9..711656710190 100644
--- a/arch/riscv/kernel/asm-offsets.c
+++ b/arch/riscv/kernel/asm-offsets.c
@@ -7,7 +7,9 @@
 #define GENERATING_ASM_OFFSETS
 
 #include <linux/kbuild.h>
+#include <linux/mm.h>
 #include <linux/sched.h>
+#include <asm/kvm_host.h>
 #include <asm/thread_info.h>
 #include <asm/ptrace.h>
 
@@ -109,6 +111,80 @@ void asm_offsets(void)
 	OFFSET(PT_SBADADDR, pt_regs, sbadaddr);
 	OFFSET(PT_SCAUSE, pt_regs, scause);
 
+	OFFSET(KVM_ARCH_GUEST_ZERO, kvm_vcpu_arch, guest_context.zero);
+	OFFSET(KVM_ARCH_GUEST_RA, kvm_vcpu_arch, guest_context.ra);
+	OFFSET(KVM_ARCH_GUEST_SP, kvm_vcpu_arch, guest_context.sp);
+	OFFSET(KVM_ARCH_GUEST_GP, kvm_vcpu_arch, guest_context.gp);
+	OFFSET(KVM_ARCH_GUEST_TP, kvm_vcpu_arch, guest_context.tp);
+	OFFSET(KVM_ARCH_GUEST_T0, kvm_vcpu_arch, guest_context.t0);
+	OFFSET(KVM_ARCH_GUEST_T1, kvm_vcpu_arch, guest_context.t1);
+	OFFSET(KVM_ARCH_GUEST_T2, kvm_vcpu_arch, guest_context.t2);
+	OFFSET(KVM_ARCH_GUEST_S0, kvm_vcpu_arch, guest_context.s0);
+	OFFSET(KVM_ARCH_GUEST_S1, kvm_vcpu_arch, guest_context.s1);
+	OFFSET(KVM_ARCH_GUEST_A0, kvm_vcpu_arch, guest_context.a0);
+	OFFSET(KVM_ARCH_GUEST_A1, kvm_vcpu_arch, guest_context.a1);
+	OFFSET(KVM_ARCH_GUEST_A2, kvm_vcpu_arch, guest_context.a2);
+	OFFSET(KVM_ARCH_GUEST_A3, kvm_vcpu_arch, guest_context.a3);
+	OFFSET(KVM_ARCH_GUEST_A4, kvm_vcpu_arch, guest_context.a4);
+	OFFSET(KVM_ARCH_GUEST_A5, kvm_vcpu_arch, guest_context.a5);
+	OFFSET(KVM_ARCH_GUEST_A6, kvm_vcpu_arch, guest_context.a6);
+	OFFSET(KVM_ARCH_GUEST_A7, kvm_vcpu_arch, guest_context.a7);
+	OFFSET(KVM_ARCH_GUEST_S2, kvm_vcpu_arch, guest_context.s2);
+	OFFSET(KVM_ARCH_GUEST_S3, kvm_vcpu_arch, guest_context.s3);
+	OFFSET(KVM_ARCH_GUEST_S4, kvm_vcpu_arch, guest_context.s4);
+	OFFSET(KVM_ARCH_GUEST_S5, kvm_vcpu_arch, guest_context.s5);
+	OFFSET(KVM_ARCH_GUEST_S6, kvm_vcpu_arch, guest_context.s6);
+	OFFSET(KVM_ARCH_GUEST_S7, kvm_vcpu_arch, guest_context.s7);
+	OFFSET(KVM_ARCH_GUEST_S8, kvm_vcpu_arch, guest_context.s8);
+	OFFSET(KVM_ARCH_GUEST_S9, kvm_vcpu_arch, guest_context.s9);
+	OFFSET(KVM_ARCH_GUEST_S10, kvm_vcpu_arch, guest_context.s10);
+	OFFSET(KVM_ARCH_GUEST_S11, kvm_vcpu_arch, guest_context.s11);
+	OFFSET(KVM_ARCH_GUEST_T3, kvm_vcpu_arch, guest_context.t3);
+	OFFSET(KVM_ARCH_GUEST_T4, kvm_vcpu_arch, guest_context.t4);
+	OFFSET(KVM_ARCH_GUEST_T5, kvm_vcpu_arch, guest_context.t5);
+	OFFSET(KVM_ARCH_GUEST_T6, kvm_vcpu_arch, guest_context.t6);
+	OFFSET(KVM_ARCH_GUEST_SEPC, kvm_vcpu_arch, guest_context.sepc);
+	OFFSET(KVM_ARCH_GUEST_SSTATUS, kvm_vcpu_arch, guest_context.sstatus);
+	OFFSET(KVM_ARCH_GUEST_HSTATUS, kvm_vcpu_arch, guest_context.hstatus);
+
+	OFFSET(KVM_ARCH_HOST_ZERO, kvm_vcpu_arch, host_context.zero);
+	OFFSET(KVM_ARCH_HOST_RA, kvm_vcpu_arch, host_context.ra);
+	OFFSET(KVM_ARCH_HOST_SP, kvm_vcpu_arch, host_context.sp);
+	OFFSET(KVM_ARCH_HOST_GP, kvm_vcpu_arch, host_context.gp);
+	OFFSET(KVM_ARCH_HOST_TP, kvm_vcpu_arch, host_context.tp);
+	OFFSET(KVM_ARCH_HOST_T0, kvm_vcpu_arch, host_context.t0);
+	OFFSET(KVM_ARCH_HOST_T1, kvm_vcpu_arch, host_context.t1);
+	OFFSET(KVM_ARCH_HOST_T2, kvm_vcpu_arch, host_context.t2);
+	OFFSET(KVM_ARCH_HOST_S0, kvm_vcpu_arch, host_context.s0);
+	OFFSET(KVM_ARCH_HOST_S1, kvm_vcpu_arch, host_context.s1);
+	OFFSET(KVM_ARCH_HOST_A0, kvm_vcpu_arch, host_context.a0);
+	OFFSET(KVM_ARCH_HOST_A1, kvm_vcpu_arch, host_context.a1);
+	OFFSET(KVM_ARCH_HOST_A2, kvm_vcpu_arch, host_context.a2);
+	OFFSET(KVM_ARCH_HOST_A3, kvm_vcpu_arch, host_context.a3);
+	OFFSET(KVM_ARCH_HOST_A4, kvm_vcpu_arch, host_context.a4);
+	OFFSET(KVM_ARCH_HOST_A5, kvm_vcpu_arch, host_context.a5);
+	OFFSET(KVM_ARCH_HOST_A6, kvm_vcpu_arch, host_context.a6);
+	OFFSET(KVM_ARCH_HOST_A7, kvm_vcpu_arch, host_context.a7);
+	OFFSET(KVM_ARCH_HOST_S2, kvm_vcpu_arch, host_context.s2);
+	OFFSET(KVM_ARCH_HOST_S3, kvm_vcpu_arch, host_context.s3);
+	OFFSET(KVM_ARCH_HOST_S4, kvm_vcpu_arch, host_context.s4);
+	OFFSET(KVM_ARCH_HOST_S5, kvm_vcpu_arch, host_context.s5);
+	OFFSET(KVM_ARCH_HOST_S6, kvm_vcpu_arch, host_context.s6);
+	OFFSET(KVM_ARCH_HOST_S7, kvm_vcpu_arch, host_context.s7);
+	OFFSET(KVM_ARCH_HOST_S8, kvm_vcpu_arch, host_context.s8);
+	OFFSET(KVM_ARCH_HOST_S9, kvm_vcpu_arch, host_context.s9);
+	OFFSET(KVM_ARCH_HOST_S10, kvm_vcpu_arch, host_context.s10);
+	OFFSET(KVM_ARCH_HOST_S11, kvm_vcpu_arch, host_context.s11);
+	OFFSET(KVM_ARCH_HOST_T3, kvm_vcpu_arch, host_context.t3);
+	OFFSET(KVM_ARCH_HOST_T4, kvm_vcpu_arch, host_context.t4);
+	OFFSET(KVM_ARCH_HOST_T5, kvm_vcpu_arch, host_context.t5);
+	OFFSET(KVM_ARCH_HOST_T6, kvm_vcpu_arch, host_context.t6);
+	OFFSET(KVM_ARCH_HOST_SEPC, kvm_vcpu_arch, host_context.sepc);
+	OFFSET(KVM_ARCH_HOST_SSTATUS, kvm_vcpu_arch, host_context.sstatus);
+	OFFSET(KVM_ARCH_HOST_HSTATUS, kvm_vcpu_arch, host_context.hstatus);
+	OFFSET(KVM_ARCH_HOST_SSCRATCH, kvm_vcpu_arch, host_sscratch);
+	OFFSET(KVM_ARCH_HOST_STVEC, kvm_vcpu_arch, host_stvec);
+
 	/*
 	 * THREAD_{F,X}* might be larger than a S-type offset can handle, but
 	 * these are used in performance-sensitive assembly so we can't resort
diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
index 37b5a59d4f4f..845579273727 100644
--- a/arch/riscv/kvm/Makefile
+++ b/arch/riscv/kvm/Makefile
@@ -8,6 +8,6 @@ ccflags-y := -Ivirt/kvm -Iarch/riscv/kvm
 
 kvm-objs := $(common-objs-y)
 
-kvm-objs += main.o vm.o mmu.o vcpu.o vcpu_exit.o
+kvm-objs += main.o vm.o mmu.o vcpu.o vcpu_exit.o vcpu_switch.o
 
 obj-$(CONFIG_KVM)	+= kvm.o
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index b95dfc959009..7f1f07badaad 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -578,14 +578,42 @@ int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
 
 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 {
-	/* TODO: */
+	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
+	unsigned long *vsip = raw_cpu_ptr(vsip_shadow);
+
+	csr_write(CSR_VSSTATUS, csr->vsstatus);
+	csr_write(CSR_VSIE, csr->vsie);
+	csr_write(CSR_VSTVEC, csr->vstvec);
+	csr_write(CSR_VSSCRATCH, csr->vsscratch);
+	csr_write(CSR_VSEPC, csr->vsepc);
+	csr_write(CSR_VSCAUSE, csr->vscause);
+	csr_write(CSR_VSTVAL, csr->vstval);
+	csr_write(CSR_VSIP, csr->vsip);
+	*vsip = csr->vsip;
+	csr_write(CSR_VSATP, csr->vsatp);
 
 	kvm_riscv_stage2_update_hgatp(vcpu);
+
+	vcpu->cpu = cpu;
 }
 
 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 {
-	/* TODO: */
+	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
+
+	vcpu->cpu = -1;
+
+	csr_write(CSR_HGATP, 0);
+
+	csr->vsstatus = csr_read(CSR_VSSTATUS);
+	csr->vsie = csr_read(CSR_VSIE);
+	csr->vstvec = csr_read(CSR_VSTVEC);
+	csr->vsscratch = csr_read(CSR_VSSCRATCH);
+	csr->vsepc = csr_read(CSR_VSEPC);
+	csr->vscause = csr_read(CSR_VSCAUSE);
+	csr->vstval = csr_read(CSR_VSTVAL);
+	csr->vsip = csr_read(CSR_VSIP);
+	csr->vsatp = csr_read(CSR_VSATP);
 }
 
 static void kvm_riscv_check_vcpu_requests(struct kvm_vcpu *vcpu)
diff --git a/arch/riscv/kvm/vcpu_switch.S b/arch/riscv/kvm/vcpu_switch.S
new file mode 100644
index 000000000000..e1a17df1b379
--- /dev/null
+++ b/arch/riscv/kvm/vcpu_switch.S
@@ -0,0 +1,194 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/csr.h>
+
+	.text
+	.altmacro
+	.option norelax
+
+ENTRY(__kvm_riscv_switch_to)
+	/* Save Host GPRs (except A0 and T0-T6) */
+	REG_S	ra, (KVM_ARCH_HOST_RA)(a0)
+	REG_S	sp, (KVM_ARCH_HOST_SP)(a0)
+	REG_S	gp, (KVM_ARCH_HOST_GP)(a0)
+	REG_S	tp, (KVM_ARCH_HOST_TP)(a0)
+	REG_S	s0, (KVM_ARCH_HOST_S0)(a0)
+	REG_S	s1, (KVM_ARCH_HOST_S1)(a0)
+	REG_S	a1, (KVM_ARCH_HOST_A1)(a0)
+	REG_S	a2, (KVM_ARCH_HOST_A2)(a0)
+	REG_S	a3, (KVM_ARCH_HOST_A3)(a0)
+	REG_S	a4, (KVM_ARCH_HOST_A4)(a0)
+	REG_S	a5, (KVM_ARCH_HOST_A5)(a0)
+	REG_S	a6, (KVM_ARCH_HOST_A6)(a0)
+	REG_S	a7, (KVM_ARCH_HOST_A7)(a0)
+	REG_S	s2, (KVM_ARCH_HOST_S2)(a0)
+	REG_S	s3, (KVM_ARCH_HOST_S3)(a0)
+	REG_S	s4, (KVM_ARCH_HOST_S4)(a0)
+	REG_S	s5, (KVM_ARCH_HOST_S5)(a0)
+	REG_S	s6, (KVM_ARCH_HOST_S6)(a0)
+	REG_S	s7, (KVM_ARCH_HOST_S7)(a0)
+	REG_S	s8, (KVM_ARCH_HOST_S8)(a0)
+	REG_S	s9, (KVM_ARCH_HOST_S9)(a0)
+	REG_S	s10, (KVM_ARCH_HOST_S10)(a0)
+	REG_S	s11, (KVM_ARCH_HOST_S11)(a0)
+
+	/* Save Host SSTATUS, HSTATUS, SCRATCH and STVEC */
+	csrr	t0, CSR_SSTATUS
+	REG_S	t0, (KVM_ARCH_HOST_SSTATUS)(a0)
+	csrr	t1, CSR_HSTATUS
+	REG_S	t1, (KVM_ARCH_HOST_HSTATUS)(a0)
+	csrr	t2, CSR_SSCRATCH
+	REG_S	t2, (KVM_ARCH_HOST_SSCRATCH)(a0)
+	csrr	t3, CSR_STVEC
+	REG_S	t3, (KVM_ARCH_HOST_STVEC)(a0)
+
+	/* Change Host exception vector to return path */
+	la	t4, __kvm_switch_return
+	csrw	CSR_STVEC, t4
+
+	/* Restore Guest HSTATUS, SSTATUS and SEPC */
+	REG_L	t4, (KVM_ARCH_GUEST_SEPC)(a0)
+	csrw	CSR_SEPC, t4
+	REG_L	t5, (KVM_ARCH_GUEST_SSTATUS)(a0)
+	csrw	CSR_SSTATUS, t5
+	REG_L	t6, (KVM_ARCH_GUEST_HSTATUS)(a0)
+	csrw	CSR_HSTATUS, t6
+
+	/* Restore Guest GPRs (except A0) */
+	REG_L	ra, (KVM_ARCH_GUEST_RA)(a0)
+	REG_L	sp, (KVM_ARCH_GUEST_SP)(a0)
+	REG_L	gp, (KVM_ARCH_GUEST_GP)(a0)
+	REG_L	tp, (KVM_ARCH_GUEST_TP)(a0)
+	REG_L	t0, (KVM_ARCH_GUEST_T0)(a0)
+	REG_L	t1, (KVM_ARCH_GUEST_T1)(a0)
+	REG_L	t2, (KVM_ARCH_GUEST_T2)(a0)
+	REG_L	s0, (KVM_ARCH_GUEST_S0)(a0)
+	REG_L	s1, (KVM_ARCH_GUEST_S1)(a0)
+	REG_L	a1, (KVM_ARCH_GUEST_A1)(a0)
+	REG_L	a2, (KVM_ARCH_GUEST_A2)(a0)
+	REG_L	a3, (KVM_ARCH_GUEST_A3)(a0)
+	REG_L	a4, (KVM_ARCH_GUEST_A4)(a0)
+	REG_L	a5, (KVM_ARCH_GUEST_A5)(a0)
+	REG_L	a6, (KVM_ARCH_GUEST_A6)(a0)
+	REG_L	a7, (KVM_ARCH_GUEST_A7)(a0)
+	REG_L	s2, (KVM_ARCH_GUEST_S2)(a0)
+	REG_L	s3, (KVM_ARCH_GUEST_S3)(a0)
+	REG_L	s4, (KVM_ARCH_GUEST_S4)(a0)
+	REG_L	s5, (KVM_ARCH_GUEST_S5)(a0)
+	REG_L	s6, (KVM_ARCH_GUEST_S6)(a0)
+	REG_L	s7, (KVM_ARCH_GUEST_S7)(a0)
+	REG_L	s8, (KVM_ARCH_GUEST_S8)(a0)
+	REG_L	s9, (KVM_ARCH_GUEST_S9)(a0)
+	REG_L	s10, (KVM_ARCH_GUEST_S10)(a0)
+	REG_L	s11, (KVM_ARCH_GUEST_S11)(a0)
+	REG_L	t3, (KVM_ARCH_GUEST_T3)(a0)
+	REG_L	t4, (KVM_ARCH_GUEST_T4)(a0)
+	REG_L	t5, (KVM_ARCH_GUEST_T5)(a0)
+	REG_L	t6, (KVM_ARCH_GUEST_T6)(a0)
+
+	/* Save Host A0 in SSCRATCH */
+	csrw	CSR_SSCRATCH, a0
+
+	/* Restore Guest A0 */
+	REG_L	a0, (KVM_ARCH_GUEST_A0)(a0)
+
+	/* Resume Guest */
+	sret
+
+	/* Back to Host */
+	.align 2
+__kvm_switch_return:
+	/* Swap Guest A0 with SSCRATCH */
+	csrrw	a0, CSR_SSCRATCH, a0
+
+	/* Save Guest GPRs (except A0) */
+	REG_S	ra, (KVM_ARCH_GUEST_RA)(a0)
+	REG_S	sp, (KVM_ARCH_GUEST_SP)(a0)
+	REG_S	gp, (KVM_ARCH_GUEST_GP)(a0)
+	REG_S	tp, (KVM_ARCH_GUEST_TP)(a0)
+	REG_S	t0, (KVM_ARCH_GUEST_T0)(a0)
+	REG_S	t1, (KVM_ARCH_GUEST_T1)(a0)
+	REG_S	t2, (KVM_ARCH_GUEST_T2)(a0)
+	REG_S	s0, (KVM_ARCH_GUEST_S0)(a0)
+	REG_S	s1, (KVM_ARCH_GUEST_S1)(a0)
+	REG_S	a1, (KVM_ARCH_GUEST_A1)(a0)
+	REG_S	a2, (KVM_ARCH_GUEST_A2)(a0)
+	REG_S	a3, (KVM_ARCH_GUEST_A3)(a0)
+	REG_S	a4, (KVM_ARCH_GUEST_A4)(a0)
+	REG_S	a5, (KVM_ARCH_GUEST_A5)(a0)
+	REG_S	a6, (KVM_ARCH_GUEST_A6)(a0)
+	REG_S	a7, (KVM_ARCH_GUEST_A7)(a0)
+	REG_S	s2, (KVM_ARCH_GUEST_S2)(a0)
+	REG_S	s3, (KVM_ARCH_GUEST_S3)(a0)
+	REG_S	s4, (KVM_ARCH_GUEST_S4)(a0)
+	REG_S	s5, (KVM_ARCH_GUEST_S5)(a0)
+	REG_S	s6, (KVM_ARCH_GUEST_S6)(a0)
+	REG_S	s7, (KVM_ARCH_GUEST_S7)(a0)
+	REG_S	s8, (KVM_ARCH_GUEST_S8)(a0)
+	REG_S	s9, (KVM_ARCH_GUEST_S9)(a0)
+	REG_S	s10, (KVM_ARCH_GUEST_S10)(a0)
+	REG_S	s11, (KVM_ARCH_GUEST_S11)(a0)
+	REG_S	t3, (KVM_ARCH_GUEST_T3)(a0)
+	REG_S	t4, (KVM_ARCH_GUEST_T4)(a0)
+	REG_S	t5, (KVM_ARCH_GUEST_T5)(a0)
+	REG_S	t6, (KVM_ARCH_GUEST_T6)(a0)
+
+	/* Save Guest A0 */
+	csrr	t0, CSR_SSCRATCH
+	REG_S	t0, (KVM_ARCH_GUEST_A0)(a0)
+
+	/* Save Guest HSTATUS, SSTATUS, and SEPC */
+	csrr	t0, CSR_SEPC
+	REG_S	t0, (KVM_ARCH_GUEST_SEPC)(a0)
+	csrr	t1, CSR_SSTATUS
+	REG_S	t1, (KVM_ARCH_GUEST_SSTATUS)(a0)
+	csrr	t2, CSR_HSTATUS
+	REG_S	t2, (KVM_ARCH_GUEST_HSTATUS)(a0)
+
+	/* Restore Host SSTATUS, HSTATUS, SCRATCH and STVEC */
+	REG_L	t3, (KVM_ARCH_HOST_SSTATUS)(a0)
+	csrw	CSR_SSTATUS, t3
+	REG_L	t4, (KVM_ARCH_HOST_HSTATUS)(a0)
+	csrw	CSR_HSTATUS, t4
+	REG_L	t5, (KVM_ARCH_HOST_SSCRATCH)(a0)
+	csrw	CSR_SSCRATCH, t5
+	REG_L	t6, (KVM_ARCH_HOST_STVEC)(a0)
+	csrw	CSR_STVEC, t6
+
+	/* Restore Host GPRs (except A0 and T0-T6) */
+	REG_L	ra, (KVM_ARCH_HOST_RA)(a0)
+	REG_L	sp, (KVM_ARCH_HOST_SP)(a0)
+	REG_L	gp, (KVM_ARCH_HOST_GP)(a0)
+	REG_L	tp, (KVM_ARCH_HOST_TP)(a0)
+	REG_L	s0, (KVM_ARCH_HOST_S0)(a0)
+	REG_L	s1, (KVM_ARCH_HOST_S1)(a0)
+	REG_L	a1, (KVM_ARCH_HOST_A1)(a0)
+	REG_L	a2, (KVM_ARCH_HOST_A2)(a0)
+	REG_L	a3, (KVM_ARCH_HOST_A3)(a0)
+	REG_L	a4, (KVM_ARCH_HOST_A4)(a0)
+	REG_L	a5, (KVM_ARCH_HOST_A5)(a0)
+	REG_L	a6, (KVM_ARCH_HOST_A6)(a0)
+	REG_L	a7, (KVM_ARCH_HOST_A7)(a0)
+	REG_L	s2, (KVM_ARCH_HOST_S2)(a0)
+	REG_L	s3, (KVM_ARCH_HOST_S3)(a0)
+	REG_L	s4, (KVM_ARCH_HOST_S4)(a0)
+	REG_L	s5, (KVM_ARCH_HOST_S5)(a0)
+	REG_L	s6, (KVM_ARCH_HOST_S6)(a0)
+	REG_L	s7, (KVM_ARCH_HOST_S7)(a0)
+	REG_L	s8, (KVM_ARCH_HOST_S8)(a0)
+	REG_L	s9, (KVM_ARCH_HOST_S9)(a0)
+	REG_L	s10, (KVM_ARCH_HOST_S10)(a0)
+	REG_L	s11, (KVM_ARCH_HOST_S11)(a0)
+
+	/* Return to C code */
+	ret
+ENDPROC(__kvm_riscv_switch_to)
-- 
2.17.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v7 10/21] RISC-V: KVM: Handle MMIO exits for VCPU

[Anup Patel]

We will get stage2 page faults whenever Guest/VM access SW emulated
MMIO device or unmapped Guest RAM.

This patch implements MMIO read/write emulation by extracting MMIO
details from the trapped load/store instruction and forwarding the
MMIO read/write to user-space. The actual MMIO emulation will happen
in user-space and KVM kernel module will only take care of register
updates before resuming the trapped VCPU.

The handling for stage2 page faults for unmapped Guest RAM will be
implemeted by a separate patch later.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/riscv/include/asm/kvm_host.h |  20 ++
 arch/riscv/kvm/mmu.c              |   7 +
 arch/riscv/kvm/vcpu_exit.c        | 512 +++++++++++++++++++++++++++++-
 arch/riscv/kvm/vcpu_switch.S      |   8 +
 4 files changed, 544 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 18f1097f1d8d..2a5209fff68d 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -53,6 +53,13 @@ struct kvm_arch {
 	phys_addr_t pgd_phys;
 };
 
+struct kvm_mmio_decode {
+	unsigned long insn;
+	int len;
+	int shift;
+	int return_handled;
+};
+
 struct kvm_cpu_context {
 	unsigned long zero;
 	unsigned long ra;
@@ -141,6 +148,9 @@ struct kvm_vcpu_arch {
 	unsigned long irqs_pending;
 	unsigned long irqs_pending_mask;
 
+	/* MMIO instruction details */
+	struct kvm_mmio_decode mmio_decode;
+
 	/* VCPU power-off state */
 	bool power_off;
 
@@ -160,11 +170,21 @@ static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {}
 int kvm_riscv_setup_vsip(void);
 void kvm_riscv_cleanup_vsip(void);
 
+int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned long hva,
+			 bool is_write);
 void kvm_riscv_stage2_flush_cache(struct kvm_vcpu *vcpu);
 int kvm_riscv_stage2_alloc_pgd(struct kvm *kvm);
 void kvm_riscv_stage2_free_pgd(struct kvm *kvm);
 void kvm_riscv_stage2_update_hgatp(struct kvm_vcpu *vcpu);
 
+void __kvm_riscv_unpriv_trap(void);
+
+unsigned long kvm_riscv_vcpu_unpriv_read(struct kvm_vcpu *vcpu,
+					 bool read_insn,
+					 unsigned long guest_addr,
+					 unsigned long *trap_scause);
+void kvm_riscv_vcpu_trap_redirect(struct kvm_vcpu *vcpu,
+				  unsigned long scause, unsigned long stval);
 int kvm_riscv_vcpu_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run);
 int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 			unsigned long scause, unsigned long stval);
diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
index 04dd089b86ff..2b965f9aac07 100644
--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c
@@ -61,6 +61,13 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 	return 0;
 }
 
+int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned long hva,
+			 bool is_write)
+{
+	/* TODO: */
+	return 0;
+}
+
 void kvm_riscv_stage2_flush_cache(struct kvm_vcpu *vcpu)
 {
 	/* TODO: */
diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
index e4d7c8f0807a..d75a6c35b6c7 100644
--- a/arch/riscv/kvm/vcpu_exit.c
+++ b/arch/riscv/kvm/vcpu_exit.c
@@ -6,9 +6,437 @@
  *     Anup Patel <anup.patel@wdc.com>
  */
 
+#include <linux/bitops.h>
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/kvm_host.h>
+#include <asm/csr.h>
+
+#define INSN_MATCH_LB		0x3
+#define INSN_MASK_LB		0x707f
+#define INSN_MATCH_LH		0x1003
+#define INSN_MASK_LH		0x707f
+#define INSN_MATCH_LW		0x2003
+#define INSN_MASK_LW		0x707f
+#define INSN_MATCH_LD		0x3003
+#define INSN_MASK_LD		0x707f
+#define INSN_MATCH_LBU		0x4003
+#define INSN_MASK_LBU		0x707f
+#define INSN_MATCH_LHU		0x5003
+#define INSN_MASK_LHU		0x707f
+#define INSN_MATCH_LWU		0x6003
+#define INSN_MASK_LWU		0x707f
+#define INSN_MATCH_SB		0x23
+#define INSN_MASK_SB		0x707f
+#define INSN_MATCH_SH		0x1023
+#define INSN_MASK_SH		0x707f
+#define INSN_MATCH_SW		0x2023
+#define INSN_MASK_SW		0x707f
+#define INSN_MATCH_SD		0x3023
+#define INSN_MASK_SD		0x707f
+
+#define INSN_MATCH_C_LD		0x6000
+#define INSN_MASK_C_LD		0xe003
+#define INSN_MATCH_C_SD		0xe000
+#define INSN_MASK_C_SD		0xe003
+#define INSN_MATCH_C_LW		0x4000
+#define INSN_MASK_C_LW		0xe003
+#define INSN_MATCH_C_SW		0xc000
+#define INSN_MASK_C_SW		0xe003
+#define INSN_MATCH_C_LDSP	0x6002
+#define INSN_MASK_C_LDSP	0xe003
+#define INSN_MATCH_C_SDSP	0xe002
+#define INSN_MASK_C_SDSP	0xe003
+#define INSN_MATCH_C_LWSP	0x4002
+#define INSN_MASK_C_LWSP	0xe003
+#define INSN_MATCH_C_SWSP	0xc002
+#define INSN_MASK_C_SWSP	0xe003
+
+#define INSN_LEN(insn)		((((insn) & 0x3) < 0x3) ? 2 : 4)
+
+#ifdef CONFIG_64BIT
+#define LOG_REGBYTES		3
+#else
+#define LOG_REGBYTES		2
+#endif
+#define REGBYTES		(1 << LOG_REGBYTES)
+
+#define SH_RD			7
+#define SH_RS1			15
+#define SH_RS2			20
+#define SH_RS2C			2
+
+#define RV_X(x, s, n)		(((x) >> (s)) & ((1 << (n)) - 1))
+#define RVC_LW_IMM(x)		((RV_X(x, 6, 1) << 2) | \
+				 (RV_X(x, 10, 3) << 3) | \
+				 (RV_X(x, 5, 1) << 6))
+#define RVC_LD_IMM(x)		((RV_X(x, 10, 3) << 3) | \
+				 (RV_X(x, 5, 2) << 6))
+#define RVC_LWSP_IMM(x)		((RV_X(x, 4, 3) << 2) | \
+				 (RV_X(x, 12, 1) << 5) | \
+				 (RV_X(x, 2, 2) << 6))
+#define RVC_LDSP_IMM(x)		((RV_X(x, 5, 2) << 3) | \
+				 (RV_X(x, 12, 1) << 5) | \
+				 (RV_X(x, 2, 3) << 6))
+#define RVC_SWSP_IMM(x)		((RV_X(x, 9, 4) << 2) | \
+				 (RV_X(x, 7, 2) << 6))
+#define RVC_SDSP_IMM(x)		((RV_X(x, 10, 3) << 3) | \
+				 (RV_X(x, 7, 3) << 6))
+#define RVC_RS1S(insn)		(8 + RV_X(insn, SH_RD, 3))
+#define RVC_RS2S(insn)		(8 + RV_X(insn, SH_RS2C, 3))
+#define RVC_RS2(insn)		RV_X(insn, SH_RS2C, 5)
+
+#define SHIFT_RIGHT(x, y)		\
+	((y) < 0 ? ((x) << -(y)) : ((x) >> (y)))
+
+#define REG_MASK			\
+	((1 << (5 + LOG_REGBYTES)) - (1 << LOG_REGBYTES))
+
+#define REG_OFFSET(insn, pos)		\
+	(SHIFT_RIGHT((insn), (pos) - LOG_REGBYTES) & REG_MASK)
+
+#define REG_PTR(insn, pos, regs)	\
+	(ulong *)((ulong)(regs) + REG_OFFSET(insn, pos))
+
+#define GET_RM(insn)		(((insn) >> 12) & 7)
+
+#define GET_RS1(insn, regs)	(*REG_PTR(insn, SH_RS1, regs))
+#define GET_RS2(insn, regs)	(*REG_PTR(insn, SH_RS2, regs))
+#define GET_RS1S(insn, regs)	(*REG_PTR(RVC_RS1S(insn), 0, regs))
+#define GET_RS2S(insn, regs)	(*REG_PTR(RVC_RS2S(insn), 0, regs))
+#define GET_RS2C(insn, regs)	(*REG_PTR(insn, SH_RS2C, regs))
+#define GET_SP(regs)		(*REG_PTR(2, 0, regs))
+#define SET_RD(insn, regs, val)	(*REG_PTR(insn, SH_RD, regs) = (val))
+#define IMM_I(insn)		((s32)(insn) >> 20)
+#define IMM_S(insn)		(((s32)(insn) >> 25 << 5) | \
+				 (s32)(((insn) >> 7) & 0x1f))
+#define MASK_FUNCT3		0x7000
+
+static int emulate_load(struct kvm_vcpu *vcpu, struct kvm_run *run,
+			unsigned long fault_addr)
+{
+	int shift = 0, len = 0;
+	unsigned long ut_scause = 0;
+	struct kvm_cpu_context *ct = &vcpu->arch.guest_context;
+	ulong insn = kvm_riscv_vcpu_unpriv_read(vcpu, true, ct->sepc,
+						&ut_scause);
+
+	/* Redirect trap if we failed to read instruction */
+	if (ut_scause) {
+		if (ut_scause == EXC_LOAD_PAGE_FAULT)
+			ut_scause = EXC_INST_PAGE_FAULT;
+		kvm_riscv_vcpu_trap_redirect(vcpu, ut_scause, ct->sepc);
+		return 1;
+	}
+
+	/* Decode length of MMIO and shift */
+	if ((insn & INSN_MASK_LW) == INSN_MATCH_LW) {
+		len = 4;
+		shift = 8 * (sizeof(ulong) - len);
+	} else if ((insn & INSN_MASK_LB) == INSN_MATCH_LB) {
+		len = 1;
+		shift = 8 * (sizeof(ulong) - len);
+	} else if ((insn & INSN_MASK_LBU) == INSN_MATCH_LBU) {
+		len = 1;
+		shift = 8 * (sizeof(ulong) - len);
+#ifdef CONFIG_64BIT
+	} else if ((insn & INSN_MASK_LD) == INSN_MATCH_LD) {
+		len = 8;
+		shift = 8 * (sizeof(ulong) - len);
+	} else if ((insn & INSN_MASK_LWU) == INSN_MATCH_LWU) {
+		len = 4;
+#endif
+	} else if ((insn & INSN_MASK_LH) == INSN_MATCH_LH) {
+		len = 2;
+		shift = 8 * (sizeof(ulong) - len);
+	} else if ((insn & INSN_MASK_LHU) == INSN_MATCH_LHU) {
+		len = 2;
+#ifdef CONFIG_RISCV_ISA_C
+#ifdef CONFIG_64BIT
+	} else if ((insn & INSN_MASK_C_LD) == INSN_MATCH_C_LD) {
+		len = 8;
+		shift = 8 * (sizeof(ulong) - len);
+		insn = RVC_RS2S(insn) << SH_RD;
+	} else if ((insn & INSN_MASK_C_LDSP) == INSN_MATCH_C_LDSP &&
+		   ((insn >> SH_RD) & 0x1f)) {
+		len = 8;
+		shift = 8 * (sizeof(ulong) - len);
+#endif
+	} else if ((insn & INSN_MASK_C_LW) == INSN_MATCH_C_LW) {
+		len = 4;
+		shift = 8 * (sizeof(ulong) - len);
+		insn = RVC_RS2S(insn) << SH_RD;
+	} else if ((insn & INSN_MASK_C_LWSP) == INSN_MATCH_C_LWSP &&
+		   ((insn >> SH_RD) & 0x1f)) {
+		len = 4;
+		shift = 8 * (sizeof(ulong) - len);
+#endif
+	} else {
+		return -ENOTSUPP;
+	}
+
+	/* Fault address should be aligned to length of MMIO */
+	if (fault_addr & (len - 1))
+		return -EIO;
+
+	/* Save instruction decode info */
+	vcpu->arch.mmio_decode.insn = insn;
+	vcpu->arch.mmio_decode.shift = shift;
+	vcpu->arch.mmio_decode.len = len;
+	vcpu->arch.mmio_decode.return_handled = 0;
+
+	/* Exit to userspace for MMIO emulation */
+	vcpu->stat.mmio_exit_user++;
+	run->exit_reason = KVM_EXIT_MMIO;
+	run->mmio.is_write = false;
+	run->mmio.phys_addr = fault_addr;
+	run->mmio.len = len;
+
+	return 0;
+}
+
+static int emulate_store(struct kvm_vcpu *vcpu, struct kvm_run *run,
+			 unsigned long fault_addr)
+{
+	u8 data8;
+	u16 data16;
+	u32 data32;
+	u64 data64;
+	ulong data;
+	int len = 0;
+	unsigned long ut_scause = 0;
+	struct kvm_cpu_context *ct = &vcpu->arch.guest_context;
+	ulong insn = kvm_riscv_vcpu_unpriv_read(vcpu, true, ct->sepc,
+						&ut_scause);
+
+	/* Redirect trap if we failed to read instruction */
+	if (ut_scause) {
+		if (ut_scause == EXC_LOAD_PAGE_FAULT)
+			ut_scause = EXC_INST_PAGE_FAULT;
+		kvm_riscv_vcpu_trap_redirect(vcpu, ut_scause, ct->sepc);
+		return 1;
+	}
+
+	data = GET_RS2(insn, &vcpu->arch.guest_context);
+	data8 = data16 = data32 = data64 = data;
+
+	if ((insn & INSN_MASK_SW) == INSN_MATCH_SW) {
+		len = 4;
+	} else if ((insn & INSN_MASK_SB) == INSN_MATCH_SB) {
+		len = 1;
+#ifdef CONFIG_64BIT
+	} else if ((insn & INSN_MASK_SD) == INSN_MATCH_SD) {
+		len = 8;
+#endif
+	} else if ((insn & INSN_MASK_SH) == INSN_MATCH_SH) {
+		len = 2;
+#ifdef CONFIG_RISCV_ISA_C
+#ifdef CONFIG_64BIT
+	} else if ((insn & INSN_MASK_C_SD) == INSN_MATCH_C_SD) {
+		len = 8;
+		data64 = GET_RS2S(insn, &vcpu->arch.guest_context);
+	} else if ((insn & INSN_MASK_C_SDSP) == INSN_MATCH_C_SDSP &&
+		   ((insn >> SH_RD) & 0x1f)) {
+		len = 8;
+		data64 = GET_RS2C(insn, &vcpu->arch.guest_context);
+#endif
+	} else if ((insn & INSN_MASK_C_SW) == INSN_MATCH_C_SW) {
+		len = 4;
+		data32 = GET_RS2S(insn, &vcpu->arch.guest_context);
+	} else if ((insn & INSN_MASK_C_SWSP) == INSN_MATCH_C_SWSP &&
+		   ((insn >> SH_RD) & 0x1f)) {
+		len = 4;
+		data32 = GET_RS2C(insn, &vcpu->arch.guest_context);
+#endif
+	} else {
+		return -ENOTSUPP;
+	}
+
+	/* Fault address should be aligned to length of MMIO */
+	if (fault_addr & (len - 1))
+		return -EIO;
+
+	/* Save instruction decode info */
+	vcpu->arch.mmio_decode.insn = insn;
+	vcpu->arch.mmio_decode.shift = 0;
+	vcpu->arch.mmio_decode.len = len;
+	vcpu->arch.mmio_decode.return_handled = 0;
+
+	/* Copy data to kvm_run instance */
+	switch (len) {
+	case 1:
+		*((u8 *)run->mmio.data) = data8;
+		break;
+	case 2:
+		*((u16 *)run->mmio.data) = data16;
+		break;
+	case 4:
+		*((u32 *)run->mmio.data) = data32;
+		break;
+	case 8:
+		*((u64 *)run->mmio.data) = data64;
+		break;
+	default:
+		return -ENOTSUPP;
+	};
+
+	/* Exit to userspace for MMIO emulation */
+	vcpu->stat.mmio_exit_user++;
+	run->exit_reason = KVM_EXIT_MMIO;
+	run->mmio.is_write = true;
+	run->mmio.phys_addr = fault_addr;
+	run->mmio.len = len;
+
+	return 0;
+}
+
+static int stage2_page_fault(struct kvm_vcpu *vcpu, struct kvm_run *run,
+			     unsigned long scause, unsigned long stval)
+{
+	struct kvm_memory_slot *memslot;
+	unsigned long hva;
+	bool writable;
+	gfn_t gfn;
+	int ret;
+
+	gfn = stval >> PAGE_SHIFT;
+	memslot = gfn_to_memslot(vcpu->kvm, gfn);
+	hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);
+
+	if (kvm_is_error_hva(hva) ||
+	    (scause == EXC_STORE_PAGE_FAULT && !writable)) {
+		switch (scause) {
+		case EXC_LOAD_PAGE_FAULT:
+			return emulate_load(vcpu, run, stval);
+		case EXC_STORE_PAGE_FAULT:
+			return emulate_store(vcpu, run, stval);
+		default:
+			return -ENOTSUPP;
+		};
+	}
+
+	ret = kvm_riscv_stage2_map(vcpu, stval, hva,
+			(scause == EXC_STORE_PAGE_FAULT) ? true : false);
+	if (ret < 0)
+		return ret;
+
+	return 1;
+}
+
+#define STR(x)		XSTR(x)
+#define XSTR(x)		#x
+
+/**
+ * kvm_riscv_vcpu_unpriv_read -- Read machine word from Guest memory
+ *
+ * @vcpu: The VCPU pointer
+ * @read_insn: Flag representing whether we are reading instruction
+ * @guest_addr: Guest address to read
+ * @trap_scause: Output pointer for unprivilege trap cause
+ * @trap_stval: Output pointer for unprivilege trap value
+ */
+unsigned long kvm_riscv_vcpu_unpriv_read(struct kvm_vcpu *vcpu,
+					 bool read_insn,
+					 unsigned long guest_addr,
+					 unsigned long *trap_scause)
+{
+	register unsigned long tilen asm("a0");
+	register unsigned long tscause asm("a1");
+	register unsigned long val asm("a2");
+	register unsigned long addr asm("a3") = guest_addr;
+	unsigned long guest_sstatus =
+			vcpu->arch.guest_context.sstatus | SR_MXR;
+	unsigned long guest_hstatus =
+			vcpu->arch.guest_context.hstatus | HSTATUS_SPRV;
+	unsigned long guest_vsstatus, old_stvec, tmp;
+
+	guest_sstatus = csr_swap(CSR_SSTATUS, guest_sstatus);
+	old_stvec = csr_swap(CSR_STVEC, (ulong)&__kvm_riscv_unpriv_trap);
+
+	if (read_insn) {
+		guest_vsstatus = csr_read_set(CSR_VSSTATUS, SR_MXR);
+		asm volatile ("\n"
+			"csrrw %[hstatus], " STR(CSR_HSTATUS) ", %[hstatus]\n"
+			"li %[tilen], 4\n"
+			"li %[tscause], 0\n"
+			"lhu %[val], (%[addr])\n"
+			"andi %[tmp], %[val], 3\n"
+			"addi %[tmp], %[tmp], -3\n"
+			"bne %[tmp], zero, 2f\n"
+			"lhu %[tmp], 2(%[addr])\n"
+			"sll %[tmp], %[tmp], 16\n"
+			"add %[val], %[val], %[tmp]\n"
+			"2: csrw " STR(CSR_HSTATUS) ", %[hstatus]"
+		: [hstatus] "+&r"(guest_hstatus), [val] "=&r" (val),
+		  [tmp] "=&r" (tmp), [tilen] "+&r" (tilen),
+		  [tscause] "+&r" (tscause)
+		: [addr] "r" (addr));
+		csr_write(CSR_VSSTATUS, guest_vsstatus);
+	} else {
+		asm volatile ("\n"
+			"csrrw %[hstatus], " STR(CSR_HSTATUS) ", %[hstatus]\n"
+#ifndef CONFIG_RISCV_ISA_C
+			"li %[tilen], 4\n"
+#else
+			"li %[tilen], 2\n"
+#endif
+			"li %[tscause], 0\n"
+#ifdef CONFIG_64BIT
+			"ld %[val], (%[addr])\n"
+#else
+			"lw %[val], (%[addr])\n"
+#endif
+			"csrw " STR(CSR_HSTATUS) ", %[hstatus]"
+		: [hstatus] "+&r"(guest_hstatus),
+		  [val] "=&r" (val), [tilen] "+&r" (tilen),
+		  [tscause] "+&r" (tscause)
+		: [addr] "r" (addr));
+	}
+
+	csr_write(CSR_STVEC, old_stvec);
+	csr_write(CSR_SSTATUS, guest_sstatus);
+
+	*trap_scause = tscause;
+
+	return val;
+}
+
+/**
+ * kvm_riscv_vcpu_trap_redirect -- Redirect trap to Guest
+ *
+ * @vcpu: The VCPU pointer
+ * @scause: Trap exception cause
+ * @stval: Trap value
+ */
+void kvm_riscv_vcpu_trap_redirect(struct kvm_vcpu *vcpu,
+				  unsigned long scause, unsigned long stval)
+{
+	unsigned long vsstatus = csr_read(CSR_VSSTATUS);
+
+	/* Change Guest SSTATUS.SPP bit */
+	vsstatus &= ~SR_SPP;
+	if (vcpu->arch.guest_context.sstatus & SR_SPP)
+		vsstatus |= SR_SPP;
+
+	/* Change Guest SSTATUS.SPIE bit */
+	vsstatus &= ~SR_SPIE;
+	if (vsstatus & SR_SIE)
+		vsstatus |= SR_SPIE;
+
+	/* Clear Guest SSTATUS.SIE bit */
+	vsstatus &= ~SR_SIE;
+
+	/* Update Guest SSTATUS */
+	csr_write(CSR_VSSTATUS, vsstatus);
+
+	/* Update Guest SCAUSE, STVAL, and SEPC */
+	csr_write(CSR_VSCAUSE, scause);
+	csr_write(CSR_VSTVAL, stval);
+	csr_write(CSR_VSEPC, vcpu->arch.guest_context.sepc);
+
+	/* Set Guest PC to Guest exception vector */
+	vcpu->arch.guest_context.sepc = csr_read(CSR_VSTVEC);
+}
 
 /**
  * kvm_riscv_vcpu_mmio_return -- Handle MMIO loads after user space emulation
@@ -19,7 +447,54 @@
  */
 int kvm_riscv_vcpu_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
 {
-	/* TODO: */
+	u8 data8;
+	u16 data16;
+	u32 data32;
+	u64 data64;
+	ulong insn;
+	int len, shift;
+
+	if (vcpu->arch.mmio_decode.return_handled)
+		return 0;
+
+	vcpu->arch.mmio_decode.return_handled = 1;
+	insn = vcpu->arch.mmio_decode.insn;
+
+	if (run->mmio.is_write)
+		goto done;
+
+	len = vcpu->arch.mmio_decode.len;
+	shift = vcpu->arch.mmio_decode.shift;
+
+	switch (len) {
+	case 1:
+		data8 = *((u8 *)run->mmio.data);
+		SET_RD(insn, &vcpu->arch.guest_context,
+			(ulong)data8 << shift >> shift);
+		break;
+	case 2:
+		data16 = *((u16 *)run->mmio.data);
+		SET_RD(insn, &vcpu->arch.guest_context,
+			(ulong)data16 << shift >> shift);
+		break;
+	case 4:
+		data32 = *((u32 *)run->mmio.data);
+		SET_RD(insn, &vcpu->arch.guest_context,
+			(ulong)data32 << shift >> shift);
+		break;
+	case 8:
+		data64 = *((u64 *)run->mmio.data);
+		SET_RD(insn, &vcpu->arch.guest_context,
+			(ulong)data64 << shift >> shift);
+		break;
+	default:
+		return -ENOTSUPP;
+	};
+
+done:
+	/* Move to next instruction */
+	vcpu->arch.guest_context.sepc += INSN_LEN(insn);
+
 	return 0;
 }
 
@@ -30,6 +505,37 @@ int kvm_riscv_vcpu_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
 int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 			unsigned long scause, unsigned long stval)
 {
-	/* TODO: */
-	return 0;
+	int ret;
+
+	/* If we got host interrupt then do nothing */
+	if (scause & SCAUSE_IRQ_FLAG)
+		return 1;
+
+	/* Handle guest traps */
+	ret = -EFAULT;
+	run->exit_reason = KVM_EXIT_UNKNOWN;
+	switch (scause) {
+	case EXC_INST_PAGE_FAULT:
+	case EXC_LOAD_PAGE_FAULT:
+	case EXC_STORE_PAGE_FAULT:
+		if ((vcpu->arch.guest_context.hstatus & HSTATUS_SPV) &&
+		    (vcpu->arch.guest_context.hstatus & HSTATUS_STL))
+			ret = stage2_page_fault(vcpu, run, scause, stval);
+		break;
+	default:
+		break;
+	};
+
+	/* Print details in-case of error */
+	if (ret < 0) {
+		kvm_err("VCPU exit error %d\n", ret);
+		kvm_err("SEPC=0x%lx SSTATUS=0x%lx HSTATUS=0x%lx\n",
+			vcpu->arch.guest_context.sepc,
+			vcpu->arch.guest_context.sstatus,
+			vcpu->arch.guest_context.hstatus);
+		kvm_err("SCAUSE=0x%lx STVAL=0x%lx\n",
+			scause, stval);
+	}
+
+	return ret;
 }
diff --git a/arch/riscv/kvm/vcpu_switch.S b/arch/riscv/kvm/vcpu_switch.S
index e1a17df1b379..ee45c331666f 100644
--- a/arch/riscv/kvm/vcpu_switch.S
+++ b/arch/riscv/kvm/vcpu_switch.S
@@ -192,3 +192,11 @@ __kvm_switch_return:
 	/* Return to C code */
 	ret
 ENDPROC(__kvm_riscv_switch_to)
+
+ENTRY(__kvm_riscv_unpriv_trap)
+	csrr	a1, CSR_SEPC
+	add	a1, a1, a0
+	csrw	CSR_SEPC, a1
+	csrr	a1, CSR_SCAUSE
+	sret
+ENDPROC(__kvm_riscv_unpriv_trap)
-- 
2.17.1


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Re: [PATCH v7 10/21] RISC-V: KVM: Handle MMIO exits for VCPU

[Alexander Graf]

On 04.09.19 18:15, Anup Patel wrote:
> We will get stage2 page faults whenever Guest/VM access SW emulated
> MMIO device or unmapped Guest RAM.
> 
> This patch implements MMIO read/write emulation by extracting MMIO
> details from the trapped load/store instruction and forwarding the
> MMIO read/write to user-space. The actual MMIO emulation will happen
> in user-space and KVM kernel module will only take care of register
> updates before resuming the trapped VCPU.
> 
> The handling for stage2 page faults for unmapped Guest RAM will be
> implemeted by a separate patch later.
> 
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

This version is indeed much better. I would not mind a bit more 
documentation when it comes to implicit register value assumptions (a0, 
a1 in the trap handler), but the code is small enough that someone who 
cares can figure it out quickly enough.

Reviewed-by: Alexander Graf <graf@amazon.com>


Alex



Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879


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Re: [PATCH v7 10/21] RISC-V: KVM: Handle MMIO exits for VCPU

[Paolo Bonzini]

On 04/09/19 18:15, Anup Patel wrote:
> +	unsigned long guest_sstatus =
> +			vcpu->arch.guest_context.sstatus | SR_MXR;
> +	unsigned long guest_hstatus =
> +			vcpu->arch.guest_context.hstatus | HSTATUS_SPRV;
> +	unsigned long guest_vsstatus, old_stvec, tmp;
> +
> +	guest_sstatus = csr_swap(CSR_SSTATUS, guest_sstatus);
> +	old_stvec = csr_swap(CSR_STVEC, (ulong)&__kvm_riscv_unpriv_trap);
> +
> +	if (read_insn) {
> +		guest_vsstatus = csr_read_set(CSR_VSSTATUS, SR_MXR);

Is this needed?  IIUC SSTATUS.MXR encompasses a wider set of permissions:

  The HS-level MXR bit makes any executable page readable.  {\tt
  vsstatus}.MXR makes readable those pages marked executable at the VS
  translation level, but only if readable at the guest-physical
  translation level.

So it should be enough to set SSTATUS.MXR=1 I think.  But you also
shouldn't set SSTATUS.MXR=1 in the !read_insn case.

Also, you can drop the irq save/restore (which is already a save/restore
of SSTATUS) since you already write 0 to SSTATUS.SIE in your csr_swap.
Perhaps add a BUG_ON(guest_sstatus & SR_SIE) before the csr_swap?

> +		asm volatile ("\n"
> +			"csrrw %[hstatus], " STR(CSR_HSTATUS) ", %[hstatus]\n"
> +			"li %[tilen], 4\n"
> +			"li %[tscause], 0\n"
> +			"lhu %[val], (%[addr])\n"
> +			"andi %[tmp], %[val], 3\n"
> +			"addi %[tmp], %[tmp], -3\n"
> +			"bne %[tmp], zero, 2f\n"
> +			"lhu %[tmp], 2(%[addr])\n"
> +			"sll %[tmp], %[tmp], 16\n"
> +			"add %[val], %[val], %[tmp]\n"
> +			"2: csrw " STR(CSR_HSTATUS) ", %[hstatus]"
> +		: [hstatus] "+&r"(guest_hstatus), [val] "=&r" (val),
> +		  [tmp] "=&r" (tmp), [tilen] "+&r" (tilen),
> +		  [tscause] "+&r" (tscause)
> +		: [addr] "r" (addr));
> +		csr_write(CSR_VSSTATUS, guest_vsstatus);

> 
> +#ifndef CONFIG_RISCV_ISA_C
> +			"li %[tilen], 4\n"
> +#else
> +			"li %[tilen], 2\n"
> +#endif

Can you use an assembler directive to force using a non-compressed
format for ld and lw?  This would get rid of tilen, which is costing 6
bytes (if I did the RVC math right) in order to save two. :)

Paolo

> +			"li %[tscause], 0\n"
> +#ifdef CONFIG_64BIT
> +			"ld %[val], (%[addr])\n"
> +#else
> +			"lw %[val], (%[addr])\n"
> +#endif

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Re: [PATCH v7 10/21] RISC-V: KVM: Handle MMIO exits for VCPU

[Anup Patel]

On Mon, Sep 23, 2019 at 4:42 PM Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 04/09/19 18:15, Anup Patel wrote:
> > +     unsigned long guest_sstatus =
> > +                     vcpu->arch.guest_context.sstatus | SR_MXR;
> > +     unsigned long guest_hstatus =
> > +                     vcpu->arch.guest_context.hstatus | HSTATUS_SPRV;
> > +     unsigned long guest_vsstatus, old_stvec, tmp;
> > +
> > +     guest_sstatus = csr_swap(CSR_SSTATUS, guest_sstatus);
> > +     old_stvec = csr_swap(CSR_STVEC, (ulong)&__kvm_riscv_unpriv_trap);
> > +
> > +     if (read_insn) {
> > +             guest_vsstatus = csr_read_set(CSR_VSSTATUS, SR_MXR);
>
> Is this needed?  IIUC SSTATUS.MXR encompasses a wider set of permissions:
>
>   The HS-level MXR bit makes any executable page readable.  {\tt
>   vsstatus}.MXR makes readable those pages marked executable at the VS
>   translation level, but only if readable at the guest-physical
>   translation level.
>
> So it should be enough to set SSTATUS.MXR=1 I think.  But you also
> shouldn't set SSTATUS.MXR=1 in the !read_insn case.

I was being overly cautious here. Initially, I thought SSTATUS.MXR
applies only to Stage2 and VSSTATUS.MXR applies only to Stage1.

I agree with you. The HS-mode should only need to set SSTATUS.MXR.

>
> Also, you can drop the irq save/restore (which is already a save/restore
> of SSTATUS) since you already write 0 to SSTATUS.SIE in your csr_swap.
> Perhaps add a BUG_ON(guest_sstatus & SR_SIE) before the csr_swap?

I had already dropped irq save/restore in v7 series and having BUG_ON()
on guest_sstatus here would be better.

>
> > +             asm volatile ("\n"
> > +                     "csrrw %[hstatus], " STR(CSR_HSTATUS) ", %[hstatus]\n"
> > +                     "li %[tilen], 4\n"
> > +                     "li %[tscause], 0\n"
> > +                     "lhu %[val], (%[addr])\n"
> > +                     "andi %[tmp], %[val], 3\n"
> > +                     "addi %[tmp], %[tmp], -3\n"
> > +                     "bne %[tmp], zero, 2f\n"
> > +                     "lhu %[tmp], 2(%[addr])\n"
> > +                     "sll %[tmp], %[tmp], 16\n"
> > +                     "add %[val], %[val], %[tmp]\n"
> > +                     "2: csrw " STR(CSR_HSTATUS) ", %[hstatus]"
> > +             : [hstatus] "+&r"(guest_hstatus), [val] "=&r" (val),
> > +               [tmp] "=&r" (tmp), [tilen] "+&r" (tilen),
> > +               [tscause] "+&r" (tscause)
> > +             : [addr] "r" (addr));
> > +             csr_write(CSR_VSSTATUS, guest_vsstatus);
>
> >
> > +#ifndef CONFIG_RISCV_ISA_C
> > +                     "li %[tilen], 4\n"
> > +#else
> > +                     "li %[tilen], 2\n"
> > +#endif
>
> Can you use an assembler directive to force using a non-compressed
> format for ld and lw?  This would get rid of tilen, which is costing 6
> bytes (if I did the RVC math right) in order to save two. :)

I tried looking for it but could not find any assembler directive
to selectively turn-off instruction compression.

>
> Paolo
>
> > +                     "li %[tscause], 0\n"
> > +#ifdef CONFIG_64BIT
> > +                     "ld %[val], (%[addr])\n"
> > +#else
> > +                     "lw %[val], (%[addr])\n"
> > +#endif

Regards,
Anup

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Re: [PATCH v7 10/21] RISC-V: KVM: Handle MMIO exits for VCPU

[Paolo Bonzini]

On 23/09/19 15:09, Anup Patel wrote:
>>> +#ifndef CONFIG_RISCV_ISA_C
>>> +                     "li %[tilen], 4\n"
>>> +#else
>>> +                     "li %[tilen], 2\n"
>>> +#endif
>>
>> Can you use an assembler directive to force using a non-compressed
>> format for ld and lw?  This would get rid of tilen, which is costing 6
>> bytes (if I did the RVC math right) in order to save two. :)
> 
> I tried looking for it but could not find any assembler directive
> to selectively turn-off instruction compression.

".option norvc"?

Paolo

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Re: [PATCH v7 10/21] RISC-V: KVM: Handle MMIO exits for VCPU

[Anup Patel]

On Mon, Sep 23, 2019 at 7:03 PM Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 23/09/19 15:09, Anup Patel wrote:
> >>> +#ifndef CONFIG_RISCV_ISA_C
> >>> +                     "li %[tilen], 4\n"
> >>> +#else
> >>> +                     "li %[tilen], 2\n"
> >>> +#endif
> >>
> >> Can you use an assembler directive to force using a non-compressed
> >> format for ld and lw?  This would get rid of tilen, which is costing 6
> >> bytes (if I did the RVC math right) in order to save two. :)
> >
> > I tried looking for it but could not find any assembler directive
> > to selectively turn-off instruction compression.
>
> ".option norvc"?

Thanks for the hint. I will try ".option norvc"

Regards,
Anup

>
> Paolo

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Re: [PATCH v7 10/21] RISC-V: KVM: Handle MMIO exits for VCPU

[Palmer Dabbelt]

On Mon, 23 Sep 2019 04:12:17 PDT (-0700), pbonzini@redhat.com wrote:
> On 04/09/19 18:15, Anup Patel wrote:
>> +	unsigned long guest_sstatus =
>> +			vcpu->arch.guest_context.sstatus | SR_MXR;
>> +	unsigned long guest_hstatus =
>> +			vcpu->arch.guest_context.hstatus | HSTATUS_SPRV;
>> +	unsigned long guest_vsstatus, old_stvec, tmp;
>> +
>> +	guest_sstatus = csr_swap(CSR_SSTATUS, guest_sstatus);
>> +	old_stvec = csr_swap(CSR_STVEC, (ulong)&__kvm_riscv_unpriv_trap);
>> +
>> +	if (read_insn) {
>> +		guest_vsstatus = csr_read_set(CSR_VSSTATUS, SR_MXR);
>
> Is this needed?  IIUC SSTATUS.MXR encompasses a wider set of permissions:
>
>   The HS-level MXR bit makes any executable page readable.  {\tt
>   vsstatus}.MXR makes readable those pages marked executable at the VS
>   translation level, but only if readable at the guest-physical
>   translation level.
>
> So it should be enough to set SSTATUS.MXR=1 I think.  But you also
> shouldn't set SSTATUS.MXR=1 in the !read_insn case.
>
> Also, you can drop the irq save/restore (which is already a save/restore
> of SSTATUS) since you already write 0 to SSTATUS.SIE in your csr_swap.
> Perhaps add a BUG_ON(guest_sstatus & SR_SIE) before the csr_swap?
>
>> +		asm volatile ("\n"
>> +			"csrrw %[hstatus], " STR(CSR_HSTATUS) ", %[hstatus]\n"
>> +			"li %[tilen], 4\n"
>> +			"li %[tscause], 0\n"
>> +			"lhu %[val], (%[addr])\n"
>> +			"andi %[tmp], %[val], 3\n"
>> +			"addi %[tmp], %[tmp], -3\n"
>> +			"bne %[tmp], zero, 2f\n"
>> +			"lhu %[tmp], 2(%[addr])\n"
>> +			"sll %[tmp], %[tmp], 16\n"
>> +			"add %[val], %[val], %[tmp]\n"
>> +			"2: csrw " STR(CSR_HSTATUS) ", %[hstatus]"
>> +		: [hstatus] "+&r"(guest_hstatus), [val] "=&r" (val),
>> +		  [tmp] "=&r" (tmp), [tilen] "+&r" (tilen),
>> +		  [tscause] "+&r" (tscause)
>> +		: [addr] "r" (addr));
>> +		csr_write(CSR_VSSTATUS, guest_vsstatus);
>
>>
>> +#ifndef CONFIG_RISCV_ISA_C
>> +			"li %[tilen], 4\n"
>> +#else
>> +			"li %[tilen], 2\n"
>> +#endif
>
> Can you use an assembler directive to force using a non-compressed
> format for ld and lw?  This would get rid of tilen, which is costing 6
> bytes (if I did the RVC math right) in order to save two. :)
>
> Paolo
>
>> +			"li %[tscause], 0\n"
>> +#ifdef CONFIG_64BIT
>> +			"ld %[val], (%[addr])\n"
>> +#else
>> +			"lw %[val], (%[addr])\n"
>> +#endif
To:          anup@brainfault.org
CC:          pbonzini@redhat.com
CC:          Anup Patel <Anup.Patel@wdc.com>
CC:          Paul Walmsley <paul.walmsley@sifive.com>
CC:          rkrcmar@redhat.com
CC:          daniel.lezcano@linaro.org
CC:          tglx@linutronix.de
CC:          graf@amazon.com
CC:          Atish Patra <Atish.Patra@wdc.com>
CC:          Alistair Francis <Alistair.Francis@wdc.com>
CC:          Damien Le Moal <Damien.LeMoal@wdc.com>
CC:          Christoph Hellwig <hch@infradead.org>
CC:          kvm@vger.kernel.org
CC:          linux-riscv@lists.infradead.org
CC:          linux-kernel@vger.kernel.org
Subject:     Re: [PATCH v7 10/21] RISC-V: KVM: Handle MMIO exits for VCPU
In-Reply-To: <CAAhSdy1-1yxMnjzppmUBxtSOAuwWaPtNZwW+QH1O7LAnEVP8pg@mail.gmail.com>

On Mon, 23 Sep 2019 06:09:43 PDT (-0700), anup@brainfault.org wrote:
> On Mon, Sep 23, 2019 at 4:42 PM Paolo Bonzini <pbonzini@redhat.com> wrote:
>>
>> On 04/09/19 18:15, Anup Patel wrote:
>> > +     unsigned long guest_sstatus =
>> > +                     vcpu->arch.guest_context.sstatus | SR_MXR;
>> > +     unsigned long guest_hstatus =
>> > +                     vcpu->arch.guest_context.hstatus | HSTATUS_SPRV;
>> > +     unsigned long guest_vsstatus, old_stvec, tmp;
>> > +
>> > +     guest_sstatus = csr_swap(CSR_SSTATUS, guest_sstatus);
>> > +     old_stvec = csr_swap(CSR_STVEC, (ulong)&__kvm_riscv_unpriv_trap);
>> > +
>> > +     if (read_insn) {
>> > +             guest_vsstatus = csr_read_set(CSR_VSSTATUS, SR_MXR);
>>
>> Is this needed?  IIUC SSTATUS.MXR encompasses a wider set of permissions:
>>
>>   The HS-level MXR bit makes any executable page readable.  {\tt
>>   vsstatus}.MXR makes readable those pages marked executable at the VS
>>   translation level, but only if readable at the guest-physical
>>   translation level.
>>
>> So it should be enough to set SSTATUS.MXR=1 I think.  But you also
>> shouldn't set SSTATUS.MXR=1 in the !read_insn case.
>
> I was being overly cautious here. Initially, I thought SSTATUS.MXR
> applies only to Stage2 and VSSTATUS.MXR applies only to Stage1.
>
> I agree with you. The HS-mode should only need to set SSTATUS.MXR.
>
>>
>> Also, you can drop the irq save/restore (which is already a save/restore
>> of SSTATUS) since you already write 0 to SSTATUS.SIE in your csr_swap.
>> Perhaps add a BUG_ON(guest_sstatus & SR_SIE) before the csr_swap?
>
> I had already dropped irq save/restore in v7 series and having BUG_ON()
> on guest_sstatus here would be better.
>
>>
>> > +             asm volatile ("\n"
>> > +                     "csrrw %[hstatus], " STR(CSR_HSTATUS) ", %[hstatus]\n"
>> > +                     "li %[tilen], 4\n"
>> > +                     "li %[tscause], 0\n"
>> > +                     "lhu %[val], (%[addr])\n"
>> > +                     "andi %[tmp], %[val], 3\n"
>> > +                     "addi %[tmp], %[tmp], -3\n"
>> > +                     "bne %[tmp], zero, 2f\n"
>> > +                     "lhu %[tmp], 2(%[addr])\n"
>> > +                     "sll %[tmp], %[tmp], 16\n"
>> > +                     "add %[val], %[val], %[tmp]\n"
>> > +                     "2: csrw " STR(CSR_HSTATUS) ", %[hstatus]"
>> > +             : [hstatus] "+&r"(guest_hstatus), [val] "=&r" (val),
>> > +               [tmp] "=&r" (tmp), [tilen] "+&r" (tilen),
>> > +               [tscause] "+&r" (tscause)
>> > +             : [addr] "r" (addr));
>> > +             csr_write(CSR_VSSTATUS, guest_vsstatus);
>>
>> >
>> > +#ifndef CONFIG_RISCV_ISA_C
>> > +                     "li %[tilen], 4\n"
>> > +#else
>> > +                     "li %[tilen], 2\n"
>> > +#endif
>>
>> Can you use an assembler directive to force using a non-compressed
>> format for ld and lw?  This would get rid of tilen, which is costing 6
>> bytes (if I did the RVC math right) in order to save two. :)
>
> I tried looking for it but could not find any assembler directive
> to selectively turn-off instruction compression.
>
>>
>> Paolo
>>
>> > +                     "li %[tscause], 0\n"
>> > +#ifdef CONFIG_64BIT
>> > +                     "ld %[val], (%[addr])\n"
>> > +#else
>> > +                     "lw %[val], (%[addr])\n"
>> > +#endif
>
> Regards,
> Anup
To:          pbonzini@redhat.com
CC:          anup@brainfault.org
CC:          Anup Patel <Anup.Patel@wdc.com>
CC:          Paul Walmsley <paul.walmsley@sifive.com>
CC:          rkrcmar@redhat.com
CC:          daniel.lezcano@linaro.org
CC:          tglx@linutronix.de
CC:          graf@amazon.com
CC:          Atish Patra <Atish.Patra@wdc.com>
CC:          Alistair Francis <Alistair.Francis@wdc.com>
CC:          Damien Le Moal <Damien.LeMoal@wdc.com>
CC:          Christoph Hellwig <hch@infradead.org>
CC:          kvm@vger.kernel.org
CC:          linux-riscv@lists.infradead.org
CC:          linux-kernel@vger.kernel.org
Subject:     Re: [PATCH v7 10/21] RISC-V: KVM: Handle MMIO exits for VCPU
In-Reply-To: <45fc3ee5-0f68-4e94-cfb3-0727ca52628f@redhat.com>

On Mon, 23 Sep 2019 06:33:14 PDT (-0700), pbonzini@redhat.com wrote:
> On 23/09/19 15:09, Anup Patel wrote:
>>>> +#ifndef CONFIG_RISCV_ISA_C
>>>> +                     "li %[tilen], 4\n"
>>>> +#else
>>>> +                     "li %[tilen], 2\n"
>>>> +#endif
>>>
>>> Can you use an assembler directive to force using a non-compressed
>>> format for ld and lw?  This would get rid of tilen, which is costing 6
>>> bytes (if I did the RVC math right) in order to save two. :)
>>
>> I tried looking for it but could not find any assembler directive
>> to selectively turn-off instruction compression.
>
> ".option norvc"?
>
> Paolo
To:          anup@brainfault.org
CC:          pbonzini@redhat.com
CC:          Anup Patel <Anup.Patel@wdc.com>
CC:          Paul Walmsley <paul.walmsley@sifive.com>
CC:          rkrcmar@redhat.com
CC:          daniel.lezcano@linaro.org
CC:          tglx@linutronix.de
CC:          graf@amazon.com
CC:          Atish Patra <Atish.Patra@wdc.com>
CC:          Alistair Francis <Alistair.Francis@wdc.com>
CC:          Damien Le Moal <Damien.LeMoal@wdc.com>
CC:          Christoph Hellwig <hch@infradead.org>
CC:          kvm@vger.kernel.org
CC:          linux-riscv@lists.infradead.org
CC:          linux-kernel@vger.kernel.org
Subject:     Re: [PATCH v7 10/21] RISC-V: KVM: Handle MMIO exits for VCPU
In-Reply-To: <CAAhSdy29gi2d9c9tumtO68QbB=_+yUYp+ikN3dQ-wa2e-Lesfw@mail.gmail.com>

On Mon, 23 Sep 2019 22:07:43 PDT (-0700), anup@brainfault.org wrote:
> On Mon, Sep 23, 2019 at 7:03 PM Paolo Bonzini <pbonzini@redhat.com> wrote:
>>
>> On 23/09/19 15:09, Anup Patel wrote:
>> >>> +#ifndef CONFIG_RISCV_ISA_C
>> >>> +                     "li %[tilen], 4\n"
>> >>> +#else
>> >>> +                     "li %[tilen], 2\n"
>> >>> +#endif
>> >>
>> >> Can you use an assembler directive to force using a non-compressed
>> >> format for ld and lw?  This would get rid of tilen, which is costing 6
>> >> bytes (if I did the RVC math right) in order to save two. :)
>> >
>> > I tried looking for it but could not find any assembler directive
>> > to selectively turn-off instruction compression.
>>
>> ".option norvc"?
>
> Thanks for the hint. I will try ".option norvc"

It should be something like

    .option push
    .option norvc
    ld ...
    .option pop

which preserves C support for the rest of the file.

>
> Regards,
> Anup
>
>>
>> Paolo

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Re: [PATCH v7 10/21] RISC-V: KVM: Handle MMIO exits for VCPU

[Anup Patel]

On Wed, Oct 9, 2019 at 4:14 AM Palmer Dabbelt <palmer@sifive.com> wrote:
>
> On Mon, 23 Sep 2019 04:12:17 PDT (-0700), pbonzini@redhat.com wrote:
> > On 04/09/19 18:15, Anup Patel wrote:
> >> +    unsigned long guest_sstatus =
> >> +                    vcpu->arch.guest_context.sstatus | SR_MXR;
> >> +    unsigned long guest_hstatus =
> >> +                    vcpu->arch.guest_context.hstatus | HSTATUS_SPRV;
> >> +    unsigned long guest_vsstatus, old_stvec, tmp;
> >> +
> >> +    guest_sstatus = csr_swap(CSR_SSTATUS, guest_sstatus);
> >> +    old_stvec = csr_swap(CSR_STVEC, (ulong)&__kvm_riscv_unpriv_trap);
> >> +
> >> +    if (read_insn) {
> >> +            guest_vsstatus = csr_read_set(CSR_VSSTATUS, SR_MXR);
> >
> > Is this needed?  IIUC SSTATUS.MXR encompasses a wider set of permissions:
> >
> >   The HS-level MXR bit makes any executable page readable.  {\tt
> >   vsstatus}.MXR makes readable those pages marked executable at the VS
> >   translation level, but only if readable at the guest-physical
> >   translation level.
> >
> > So it should be enough to set SSTATUS.MXR=1 I think.  But you also
> > shouldn't set SSTATUS.MXR=1 in the !read_insn case.
> >
> > Also, you can drop the irq save/restore (which is already a save/restore
> > of SSTATUS) since you already write 0 to SSTATUS.SIE in your csr_swap.
> > Perhaps add a BUG_ON(guest_sstatus & SR_SIE) before the csr_swap?
> >
> >> +            asm volatile ("\n"
> >> +                    "csrrw %[hstatus], " STR(CSR_HSTATUS) ", %[hstatus]\n"
> >> +                    "li %[tilen], 4\n"
> >> +                    "li %[tscause], 0\n"
> >> +                    "lhu %[val], (%[addr])\n"
> >> +                    "andi %[tmp], %[val], 3\n"
> >> +                    "addi %[tmp], %[tmp], -3\n"
> >> +                    "bne %[tmp], zero, 2f\n"
> >> +                    "lhu %[tmp], 2(%[addr])\n"
> >> +                    "sll %[tmp], %[tmp], 16\n"
> >> +                    "add %[val], %[val], %[tmp]\n"
> >> +                    "2: csrw " STR(CSR_HSTATUS) ", %[hstatus]"
> >> +            : [hstatus] "+&r"(guest_hstatus), [val] "=&r" (val),
> >> +              [tmp] "=&r" (tmp), [tilen] "+&r" (tilen),
> >> +              [tscause] "+&r" (tscause)
> >> +            : [addr] "r" (addr));
> >> +            csr_write(CSR_VSSTATUS, guest_vsstatus);
> >
> >>
> >> +#ifndef CONFIG_RISCV_ISA_C
> >> +                    "li %[tilen], 4\n"
> >> +#else
> >> +                    "li %[tilen], 2\n"
> >> +#endif
> >
> > Can you use an assembler directive to force using a non-compressed
> > format for ld and lw?  This would get rid of tilen, which is costing 6
> > bytes (if I did the RVC math right) in order to save two. :)
> >
> > Paolo
> >
> >> +                    "li %[tscause], 0\n"
> >> +#ifdef CONFIG_64BIT
> >> +                    "ld %[val], (%[addr])\n"
> >> +#else
> >> +                    "lw %[val], (%[addr])\n"
> >> +#endif
> To:          anup@brainfault.org
> CC:          pbonzini@redhat.com
> CC:          Anup Patel <Anup.Patel@wdc.com>
> CC:          Paul Walmsley <paul.walmsley@sifive.com>
> CC:          rkrcmar@redhat.com
> CC:          daniel.lezcano@linaro.org
> CC:          tglx@linutronix.de
> CC:          graf@amazon.com
> CC:          Atish Patra <Atish.Patra@wdc.com>
> CC:          Alistair Francis <Alistair.Francis@wdc.com>
> CC:          Damien Le Moal <Damien.LeMoal@wdc.com>
> CC:          Christoph Hellwig <hch@infradead.org>
> CC:          kvm@vger.kernel.org
> CC:          linux-riscv@lists.infradead.org
> CC:          linux-kernel@vger.kernel.org
> Subject:     Re: [PATCH v7 10/21] RISC-V: KVM: Handle MMIO exits for VCPU
> In-Reply-To: <CAAhSdy1-1yxMnjzppmUBxtSOAuwWaPtNZwW+QH1O7LAnEVP8pg@mail.gmail.com>
>
> On Mon, 23 Sep 2019 06:09:43 PDT (-0700), anup@brainfault.org wrote:
> > On Mon, Sep 23, 2019 at 4:42 PM Paolo Bonzini <pbonzini@redhat.com> wrote:
> >>
> >> On 04/09/19 18:15, Anup Patel wrote:
> >> > +     unsigned long guest_sstatus =
> >> > +                     vcpu->arch.guest_context.sstatus | SR_MXR;
> >> > +     unsigned long guest_hstatus =
> >> > +                     vcpu->arch.guest_context.hstatus | HSTATUS_SPRV;
> >> > +     unsigned long guest_vsstatus, old_stvec, tmp;
> >> > +
> >> > +     guest_sstatus = csr_swap(CSR_SSTATUS, guest_sstatus);
> >> > +     old_stvec = csr_swap(CSR_STVEC, (ulong)&__kvm_riscv_unpriv_trap);
> >> > +
> >> > +     if (read_insn) {
> >> > +             guest_vsstatus = csr_read_set(CSR_VSSTATUS, SR_MXR);
> >>
> >> Is this needed?  IIUC SSTATUS.MXR encompasses a wider set of permissions:
> >>
> >>   The HS-level MXR bit makes any executable page readable.  {\tt
> >>   vsstatus}.MXR makes readable those pages marked executable at the VS
> >>   translation level, but only if readable at the guest-physical
> >>   translation level.
> >>
> >> So it should be enough to set SSTATUS.MXR=1 I think.  But you also
> >> shouldn't set SSTATUS.MXR=1 in the !read_insn case.
> >
> > I was being overly cautious here. Initially, I thought SSTATUS.MXR
> > applies only to Stage2 and VSSTATUS.MXR applies only to Stage1.
> >
> > I agree with you. The HS-mode should only need to set SSTATUS.MXR.
> >
> >>
> >> Also, you can drop the irq save/restore (which is already a save/restore
> >> of SSTATUS) since you already write 0 to SSTATUS.SIE in your csr_swap.
> >> Perhaps add a BUG_ON(guest_sstatus & SR_SIE) before the csr_swap?
> >
> > I had already dropped irq save/restore in v7 series and having BUG_ON()
> > on guest_sstatus here would be better.
> >
> >>
> >> > +             asm volatile ("\n"
> >> > +                     "csrrw %[hstatus], " STR(CSR_HSTATUS) ", %[hstatus]\n"
> >> > +                     "li %[tilen], 4\n"
> >> > +                     "li %[tscause], 0\n"
> >> > +                     "lhu %[val], (%[addr])\n"
> >> > +                     "andi %[tmp], %[val], 3\n"
> >> > +                     "addi %[tmp], %[tmp], -3\n"
> >> > +                     "bne %[tmp], zero, 2f\n"
> >> > +                     "lhu %[tmp], 2(%[addr])\n"
> >> > +                     "sll %[tmp], %[tmp], 16\n"
> >> > +                     "add %[val], %[val], %[tmp]\n"
> >> > +                     "2: csrw " STR(CSR_HSTATUS) ", %[hstatus]"
> >> > +             : [hstatus] "+&r"(guest_hstatus), [val] "=&r" (val),
> >> > +               [tmp] "=&r" (tmp), [tilen] "+&r" (tilen),
> >> > +               [tscause] "+&r" (tscause)
> >> > +             : [addr] "r" (addr));
> >> > +             csr_write(CSR_VSSTATUS, guest_vsstatus);
> >>
> >> >
> >> > +#ifndef CONFIG_RISCV_ISA_C
> >> > +                     "li %[tilen], 4\n"
> >> > +#else
> >> > +                     "li %[tilen], 2\n"
> >> > +#endif
> >>
> >> Can you use an assembler directive to force using a non-compressed
> >> format for ld and lw?  This would get rid of tilen, which is costing 6
> >> bytes (if I did the RVC math right) in order to save two. :)
> >
> > I tried looking for it but could not find any assembler directive
> > to selectively turn-off instruction compression.
> >
> >>
> >> Paolo
> >>
> >> > +                     "li %[tscause], 0\n"
> >> > +#ifdef CONFIG_64BIT
> >> > +                     "ld %[val], (%[addr])\n"
> >> > +#else
> >> > +                     "lw %[val], (%[addr])\n"
> >> > +#endif
> >
> > Regards,
> > Anup
> To:          pbonzini@redhat.com
> CC:          anup@brainfault.org
> CC:          Anup Patel <Anup.Patel@wdc.com>
> CC:          Paul Walmsley <paul.walmsley@sifive.com>
> CC:          rkrcmar@redhat.com
> CC:          daniel.lezcano@linaro.org
> CC:          tglx@linutronix.de
> CC:          graf@amazon.com
> CC:          Atish Patra <Atish.Patra@wdc.com>
> CC:          Alistair Francis <Alistair.Francis@wdc.com>
> CC:          Damien Le Moal <Damien.LeMoal@wdc.com>
> CC:          Christoph Hellwig <hch@infradead.org>
> CC:          kvm@vger.kernel.org
> CC:          linux-riscv@lists.infradead.org
> CC:          linux-kernel@vger.kernel.org
> Subject:     Re: [PATCH v7 10/21] RISC-V: KVM: Handle MMIO exits for VCPU
> In-Reply-To: <45fc3ee5-0f68-4e94-cfb3-0727ca52628f@redhat.com>
>
> On Mon, 23 Sep 2019 06:33:14 PDT (-0700), pbonzini@redhat.com wrote:
> > On 23/09/19 15:09, Anup Patel wrote:
> >>>> +#ifndef CONFIG_RISCV_ISA_C
> >>>> +                     "li %[tilen], 4\n"
> >>>> +#else
> >>>> +                     "li %[tilen], 2\n"
> >>>> +#endif
> >>>
> >>> Can you use an assembler directive to force using a non-compressed
> >>> format for ld and lw?  This would get rid of tilen, which is costing 6
> >>> bytes (if I did the RVC math right) in order to save two. :)
> >>
> >> I tried looking for it but could not find any assembler directive
> >> to selectively turn-off instruction compression.
> >
> > ".option norvc"?
> >
> > Paolo
> To:          anup@brainfault.org
> CC:          pbonzini@redhat.com
> CC:          Anup Patel <Anup.Patel@wdc.com>
> CC:          Paul Walmsley <paul.walmsley@sifive.com>
> CC:          rkrcmar@redhat.com
> CC:          daniel.lezcano@linaro.org
> CC:          tglx@linutronix.de
> CC:          graf@amazon.com
> CC:          Atish Patra <Atish.Patra@wdc.com>
> CC:          Alistair Francis <Alistair.Francis@wdc.com>
> CC:          Damien Le Moal <Damien.LeMoal@wdc.com>
> CC:          Christoph Hellwig <hch@infradead.org>
> CC:          kvm@vger.kernel.org
> CC:          linux-riscv@lists.infradead.org
> CC:          linux-kernel@vger.kernel.org
> Subject:     Re: [PATCH v7 10/21] RISC-V: KVM: Handle MMIO exits for VCPU
> In-Reply-To: <CAAhSdy29gi2d9c9tumtO68QbB=_+yUYp+ikN3dQ-wa2e-Lesfw@mail.gmail.com>
>
> On Mon, 23 Sep 2019 22:07:43 PDT (-0700), anup@brainfault.org wrote:
> > On Mon, Sep 23, 2019 at 7:03 PM Paolo Bonzini <pbonzini@redhat.com> wrote:
> >>
> >> On 23/09/19 15:09, Anup Patel wrote:
> >> >>> +#ifndef CONFIG_RISCV_ISA_C
> >> >>> +                     "li %[tilen], 4\n"
> >> >>> +#else
> >> >>> +                     "li %[tilen], 2\n"
> >> >>> +#endif
> >> >>
> >> >> Can you use an assembler directive to force using a non-compressed
> >> >> format for ld and lw?  This would get rid of tilen, which is costing 6
> >> >> bytes (if I did the RVC math right) in order to save two. :)
> >> >
> >> > I tried looking for it but could not find any assembler directive
> >> > to selectively turn-off instruction compression.
> >>
> >> ".option norvc"?
> >
> > Thanks for the hint. I will try ".option norvc"
>
> It should be something like
>
>     .option push
>     .option norvc
>     ld ...
>     .option pop
>
> which preserves C support for the rest of the file.

I have done exactly same thing in v8 patch series sent-out
last week.

Thanks,
Anup

>
> >
> > Regards,
> > Anup
> >
> >>
> >> Paolo

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[PATCH v7 11/21] RISC-V: KVM: Handle WFI exits for VCPU

[Anup Patel]

We get illegal instruction trap whenever Guest/VM executes WFI
instruction.

This patch handles WFI trap by blocking the trapped VCPU using
kvm_vcpu_block() API. The blocked VCPU will be automatically
resumed whenever a VCPU interrupt is injected from user-space
or from in-kernel IRQCHIP emulation.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/riscv/kvm/vcpu_exit.c | 72 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)

diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
index d75a6c35b6c7..39469f67b241 100644
--- a/arch/riscv/kvm/vcpu_exit.c
+++ b/arch/riscv/kvm/vcpu_exit.c
@@ -12,6 +12,13 @@
 #include <linux/kvm_host.h>
 #include <asm/csr.h>
 
+#define INSN_OPCODE_MASK	0x007c
+#define INSN_OPCODE_SHIFT	2
+#define INSN_OPCODE_SYSTEM	28
+
+#define INSN_MASK_WFI		0xffffff00
+#define INSN_MATCH_WFI		0x10500000
+
 #define INSN_MATCH_LB		0x3
 #define INSN_MASK_LB		0x707f
 #define INSN_MATCH_LH		0x1003
@@ -112,6 +119,67 @@
 				 (s32)(((insn) >> 7) & 0x1f))
 #define MASK_FUNCT3		0x7000
 
+static int truly_illegal_insn(struct kvm_vcpu *vcpu,
+			      struct kvm_run *run,
+			      ulong insn)
+{
+	/* Redirect trap to Guest VCPU */
+	kvm_riscv_vcpu_trap_redirect(vcpu, EXC_INST_ILLEGAL, insn);
+
+	return 1;
+}
+
+static int system_opcode_insn(struct kvm_vcpu *vcpu,
+			      struct kvm_run *run,
+			      ulong insn)
+{
+	if ((insn & INSN_MASK_WFI) == INSN_MATCH_WFI) {
+		vcpu->stat.wfi_exit_stat++;
+		if (!kvm_arch_vcpu_runnable(vcpu)) {
+			srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
+			kvm_vcpu_block(vcpu);
+			vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+			kvm_clear_request(KVM_REQ_UNHALT, vcpu);
+		}
+		vcpu->arch.guest_context.sepc += INSN_LEN(insn);
+		return 1;
+	}
+
+	return truly_illegal_insn(vcpu, run, insn);
+}
+
+static int illegal_inst_fault(struct kvm_vcpu *vcpu, struct kvm_run *run,
+			      unsigned long insn)
+{
+	unsigned long ut_scause = 0;
+	struct kvm_cpu_context *ct;
+
+	if (unlikely((insn & 3) != 3)) {
+		if (insn == 0) {
+			ct = &vcpu->arch.guest_context;
+			insn = kvm_riscv_vcpu_unpriv_read(vcpu, true,
+							  ct->sepc,
+							  &ut_scause);
+			if (ut_scause) {
+				if (ut_scause == EXC_LOAD_PAGE_FAULT)
+					ut_scause = EXC_INST_PAGE_FAULT;
+				kvm_riscv_vcpu_trap_redirect(vcpu, ut_scause,
+							     ct->sepc);
+				return 1;
+			}
+		}
+		if ((insn & 3) != 3)
+			return truly_illegal_insn(vcpu, run, insn);
+	}
+
+	switch ((insn & INSN_OPCODE_MASK) >> INSN_OPCODE_SHIFT) {
+	case INSN_OPCODE_SYSTEM:
+		return system_opcode_insn(vcpu, run, insn);
+	default:
+		return truly_illegal_insn(vcpu, run, insn);
+	}
+}
+
 static int emulate_load(struct kvm_vcpu *vcpu, struct kvm_run *run,
 			unsigned long fault_addr)
 {
@@ -515,6 +583,10 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 	ret = -EFAULT;
 	run->exit_reason = KVM_EXIT_UNKNOWN;
 	switch (scause) {
+	case EXC_INST_ILLEGAL:
+		if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV)
+			ret = illegal_inst_fault(vcpu, run, stval);
+		break;
 	case EXC_INST_PAGE_FAULT:
 	case EXC_LOAD_PAGE_FAULT:
 	case EXC_STORE_PAGE_FAULT:
-- 
2.17.1


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Re: [PATCH v7 11/21] RISC-V: KVM: Handle WFI exits for VCPU

[Alexander Graf]

On 04.09.19 18:15, Anup Patel wrote:
> We get illegal instruction trap whenever Guest/VM executes WFI
> instruction.
> 
> This patch handles WFI trap by blocking the trapped VCPU using
> kvm_vcpu_block() API. The blocked VCPU will be automatically
> resumed whenever a VCPU interrupt is injected from user-space
> or from in-kernel IRQCHIP emulation.
> 
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   arch/riscv/kvm/vcpu_exit.c | 72 ++++++++++++++++++++++++++++++++++++++
>   1 file changed, 72 insertions(+)
> 
> diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
> index d75a6c35b6c7..39469f67b241 100644
> --- a/arch/riscv/kvm/vcpu_exit.c
> +++ b/arch/riscv/kvm/vcpu_exit.c
> @@ -12,6 +12,13 @@
>   #include <linux/kvm_host.h>
>   #include <asm/csr.h>
>   
> +#define INSN_OPCODE_MASK	0x007c
> +#define INSN_OPCODE_SHIFT	2
> +#define INSN_OPCODE_SYSTEM	28
> +
> +#define INSN_MASK_WFI		0xffffff00
> +#define INSN_MATCH_WFI		0x10500000
> +
>   #define INSN_MATCH_LB		0x3
>   #define INSN_MASK_LB		0x707f
>   #define INSN_MATCH_LH		0x1003
> @@ -112,6 +119,67 @@
>   				 (s32)(((insn) >> 7) & 0x1f))
>   #define MASK_FUNCT3		0x7000
>   
> +static int truly_illegal_insn(struct kvm_vcpu *vcpu,
> +			      struct kvm_run *run,
> +			      ulong insn)
> +{
> +	/* Redirect trap to Guest VCPU */
> +	kvm_riscv_vcpu_trap_redirect(vcpu, EXC_INST_ILLEGAL, insn);
> +
> +	return 1;
> +}
> +
> +static int system_opcode_insn(struct kvm_vcpu *vcpu,
> +			      struct kvm_run *run,
> +			      ulong insn)
> +{
> +	if ((insn & INSN_MASK_WFI) == INSN_MATCH_WFI) {
> +		vcpu->stat.wfi_exit_stat++;
> +		if (!kvm_arch_vcpu_runnable(vcpu)) {
> +			srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
> +			kvm_vcpu_block(vcpu);
> +			vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
> +			kvm_clear_request(KVM_REQ_UNHALT, vcpu);
> +		}
> +		vcpu->arch.guest_context.sepc += INSN_LEN(insn);
> +		return 1;
> +	}
> +
> +	return truly_illegal_insn(vcpu, run, insn);
> +}
> +
> +static int illegal_inst_fault(struct kvm_vcpu *vcpu, struct kvm_run *run,
> +			      unsigned long insn)
> +{
> +	unsigned long ut_scause = 0;
> +	struct kvm_cpu_context *ct;
> +
> +	if (unlikely((insn & 3) != 3)) {

What do the low 2 bits mean here? Maybe you can use a define instead?


Alex




Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879


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Re: [PATCH v7 11/21] RISC-V: KVM: Handle WFI exits for VCPU

[Anup Patel]

On Mon, Sep 23, 2019 at 12:24 PM Alexander Graf <graf@amazon.com> wrote:
>
>
>
> On 04.09.19 18:15, Anup Patel wrote:
> > We get illegal instruction trap whenever Guest/VM executes WFI
> > instruction.
> >
> > This patch handles WFI trap by blocking the trapped VCPU using
> > kvm_vcpu_block() API. The blocked VCPU will be automatically
> > resumed whenever a VCPU interrupt is injected from user-space
> > or from in-kernel IRQCHIP emulation.
> >
> > Signed-off-by: Anup Patel <anup.patel@wdc.com>
> > Acked-by: Paolo Bonzini <pbonzini@redhat.com>
> > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> > ---
> >   arch/riscv/kvm/vcpu_exit.c | 72 ++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 72 insertions(+)
> >
> > diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
> > index d75a6c35b6c7..39469f67b241 100644
> > --- a/arch/riscv/kvm/vcpu_exit.c
> > +++ b/arch/riscv/kvm/vcpu_exit.c
> > @@ -12,6 +12,13 @@
> >   #include <linux/kvm_host.h>
> >   #include <asm/csr.h>
> >
> > +#define INSN_OPCODE_MASK     0x007c
> > +#define INSN_OPCODE_SHIFT    2
> > +#define INSN_OPCODE_SYSTEM   28
> > +
> > +#define INSN_MASK_WFI                0xffffff00
> > +#define INSN_MATCH_WFI               0x10500000
> > +
> >   #define INSN_MATCH_LB               0x3
> >   #define INSN_MASK_LB                0x707f
> >   #define INSN_MATCH_LH               0x1003
> > @@ -112,6 +119,67 @@
> >                                (s32)(((insn) >> 7) & 0x1f))
> >   #define MASK_FUNCT3         0x7000
> >
> > +static int truly_illegal_insn(struct kvm_vcpu *vcpu,
> > +                           struct kvm_run *run,
> > +                           ulong insn)
> > +{
> > +     /* Redirect trap to Guest VCPU */
> > +     kvm_riscv_vcpu_trap_redirect(vcpu, EXC_INST_ILLEGAL, insn);
> > +
> > +     return 1;
> > +}
> > +
> > +static int system_opcode_insn(struct kvm_vcpu *vcpu,
> > +                           struct kvm_run *run,
> > +                           ulong insn)
> > +{
> > +     if ((insn & INSN_MASK_WFI) == INSN_MATCH_WFI) {
> > +             vcpu->stat.wfi_exit_stat++;
> > +             if (!kvm_arch_vcpu_runnable(vcpu)) {
> > +                     srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
> > +                     kvm_vcpu_block(vcpu);
> > +                     vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
> > +                     kvm_clear_request(KVM_REQ_UNHALT, vcpu);
> > +             }
> > +             vcpu->arch.guest_context.sepc += INSN_LEN(insn);
> > +             return 1;
> > +     }
> > +
> > +     return truly_illegal_insn(vcpu, run, insn);
> > +}
> > +
> > +static int illegal_inst_fault(struct kvm_vcpu *vcpu, struct kvm_run *run,
> > +                           unsigned long insn)
> > +{
> > +     unsigned long ut_scause = 0;
> > +     struct kvm_cpu_context *ct;
> > +
> > +     if (unlikely((insn & 3) != 3)) {
>
> What do the low 2 bits mean here? Maybe you can use a define instead?

These bits are for instruction length (16bit or 32bit).

I will add appropriate defines for these bits.

Regards,
Anup

>
>
> Alex
>
>
>
>
> Amazon Development Center Germany GmbH
> Krausenstr. 38
> 10117 Berlin
> Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
> Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
> Sitz: Berlin
> Ust-ID: DE 289 237 879
>
>

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[PATCH v7 12/21] RISC-V: KVM: Implement VMID allocator

[Anup Patel]

We implement a simple VMID allocator for Guests/VMs which:
1. Detects number of VMID bits at boot-time
2. Uses atomic number to track VMID version and increments
   VMID version whenever we run-out of VMIDs
3. Flushes Guest TLBs on all host CPUs whenever we run-out
   of VMIDs
4. Force updates HW Stage2 VMID for each Guest VCPU whenever
   VMID changes using VCPU request KVM_REQ_UPDATE_HGATP

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
 arch/riscv/include/asm/kvm_host.h |  25 ++++++
 arch/riscv/kvm/Makefile           |   3 +-
 arch/riscv/kvm/main.c             |   4 +
 arch/riscv/kvm/tlb.S              |  43 +++++++++++
 arch/riscv/kvm/vcpu.c             |   9 +++
 arch/riscv/kvm/vm.c               |   6 ++
 arch/riscv/kvm/vmid.c             | 123 ++++++++++++++++++++++++++++++
 7 files changed, 212 insertions(+), 1 deletion(-)
 create mode 100644 arch/riscv/kvm/tlb.S
 create mode 100644 arch/riscv/kvm/vmid.c

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 2a5209fff68d..8aaf22a900be 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -27,6 +27,7 @@
 #define KVM_REQ_SLEEP \
 	KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
 #define KVM_REQ_VCPU_RESET		KVM_ARCH_REQ(1)
+#define KVM_REQ_UPDATE_HGATP		KVM_ARCH_REQ(2)
 
 struct kvm_vm_stat {
 	ulong remote_tlb_flush;
@@ -47,7 +48,19 @@ struct kvm_vcpu_stat {
 struct kvm_arch_memory_slot {
 };
 
+struct kvm_vmid {
+	/*
+	 * Writes to vmid_version and vmid happen with vmid_lock held
+	 * whereas reads happen without any lock held.
+	 */
+	unsigned long vmid_version;
+	unsigned long vmid;
+};
+
 struct kvm_arch {
+	/* stage2 vmid */
+	struct kvm_vmid vmid;
+
 	/* stage2 page table */
 	pgd_t *pgd;
 	phys_addr_t pgd_phys;
@@ -170,6 +183,12 @@ static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {}
 int kvm_riscv_setup_vsip(void);
 void kvm_riscv_cleanup_vsip(void);
 
+void __kvm_riscv_hfence_gvma_vmid_gpa(unsigned long vmid,
+				      unsigned long gpa);
+void __kvm_riscv_hfence_gvma_vmid(unsigned long vmid);
+void __kvm_riscv_hfence_gvma_gpa(unsigned long gpa);
+void __kvm_riscv_hfence_gvma_all(void);
+
 int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned long hva,
 			 bool is_write);
 void kvm_riscv_stage2_flush_cache(struct kvm_vcpu *vcpu);
@@ -177,6 +196,12 @@ int kvm_riscv_stage2_alloc_pgd(struct kvm *kvm);
 void kvm_riscv_stage2_free_pgd(struct kvm *kvm);
 void kvm_riscv_stage2_update_hgatp(struct kvm_vcpu *vcpu);
 
+void kvm_riscv_stage2_vmid_detect(void);
+unsigned long kvm_riscv_stage2_vmid_bits(void);
+int kvm_riscv_stage2_vmid_init(struct kvm *kvm);
+bool kvm_riscv_stage2_vmid_ver_changed(struct kvm_vmid *vmid);
+void kvm_riscv_stage2_vmid_update(struct kvm_vcpu *vcpu);
+
 void __kvm_riscv_unpriv_trap(void);
 
 unsigned long kvm_riscv_vcpu_unpriv_read(struct kvm_vcpu *vcpu,
diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
index 845579273727..c0f57f26c13d 100644
--- a/arch/riscv/kvm/Makefile
+++ b/arch/riscv/kvm/Makefile
@@ -8,6 +8,7 @@ ccflags-y := -Ivirt/kvm -Iarch/riscv/kvm
 
 kvm-objs := $(common-objs-y)
 
-kvm-objs += main.o vm.o mmu.o vcpu.o vcpu_exit.o vcpu_switch.o
+kvm-objs += main.o vm.o vmid.o tlb.o mmu.o
+kvm-objs += vcpu.o vcpu_exit.o vcpu_switch.o
 
 obj-$(CONFIG_KVM)	+= kvm.o
diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c
index d088247843c5..55df85184241 100644
--- a/arch/riscv/kvm/main.c
+++ b/arch/riscv/kvm/main.c
@@ -72,8 +72,12 @@ int kvm_arch_init(void *opaque)
 	if (ret)
 		return ret;
 
+	kvm_riscv_stage2_vmid_detect();
+
 	kvm_info("hypervisor extension available\n");
 
+	kvm_info("host has %ld VMID bits\n", kvm_riscv_stage2_vmid_bits());
+
 	return 0;
 }
 
diff --git a/arch/riscv/kvm/tlb.S b/arch/riscv/kvm/tlb.S
new file mode 100644
index 000000000000..453fca8d7940
--- /dev/null
+++ b/arch/riscv/kvm/tlb.S
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm.h>
+
+	.text
+	.altmacro
+	.option norelax
+
+	/*
+	 * Instruction encoding of hfence.gvma is:
+	 * 0110001 rs2(5) rs1(5) 000 00000 1110011
+	 */
+
+ENTRY(__kvm_riscv_hfence_gvma_vmid_gpa)
+	/* hfence.gvma a1, a0 */
+	.word 0x62a60073
+	ret
+ENDPROC(__kvm_riscv_hfence_gvma_vmid_gpa)
+
+ENTRY(__kvm_riscv_hfence_gvma_vmid)
+	/* hfence.gvma zero, a0 */
+	.word 0x62a00073
+	ret
+ENDPROC(__kvm_riscv_hfence_gvma_vmid)
+
+ENTRY(__kvm_riscv_hfence_gvma_gpa)
+	/* hfence.gvma a0 */
+	.word 0x62050073
+	ret
+ENDPROC(__kvm_riscv_hfence_gvma_gpa)
+
+ENTRY(__kvm_riscv_hfence_gvma_all)
+	/* hfence.gvma */
+	.word 0x62000073
+	ret
+ENDPROC(__kvm_riscv_hfence_gvma_all)
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 7f1f07badaad..66158c0b90e6 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -637,6 +637,12 @@ static void kvm_riscv_check_vcpu_requests(struct kvm_vcpu *vcpu)
 
 		if (kvm_check_request(KVM_REQ_VCPU_RESET, vcpu))
 			kvm_riscv_reset_vcpu(vcpu);
+
+		if (kvm_check_request(KVM_REQ_UPDATE_HGATP, vcpu))
+			kvm_riscv_stage2_update_hgatp(vcpu);
+
+		if (kvm_check_request(KVM_REQ_TLB_FLUSH, vcpu))
+			__kvm_riscv_hfence_gvma_all();
 	}
 }
 
@@ -699,6 +705,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		/* Check conditions before entering the guest */
 		cond_resched();
 
+		kvm_riscv_stage2_vmid_update(vcpu);
+
 		kvm_riscv_check_vcpu_requests(vcpu);
 
 		preempt_disable();
@@ -735,6 +743,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		kvm_riscv_update_vsip(vcpu);
 
 		if (ret <= 0 ||
+		    kvm_riscv_stage2_vmid_ver_changed(&vcpu->kvm->arch.vmid) ||
 		    kvm_request_pending(vcpu)) {
 			vcpu->mode = OUTSIDE_GUEST_MODE;
 			local_irq_enable();
diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c
index ac0211820521..c5aab5478c38 100644
--- a/arch/riscv/kvm/vm.c
+++ b/arch/riscv/kvm/vm.c
@@ -26,6 +26,12 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 	if (r)
 		return r;
 
+	r = kvm_riscv_stage2_vmid_init(kvm);
+	if (r) {
+		kvm_riscv_stage2_free_pgd(kvm);
+		return r;
+	}
+
 	return 0;
 }
 
diff --git a/arch/riscv/kvm/vmid.c b/arch/riscv/kvm/vmid.c
new file mode 100644
index 000000000000..69f770fa4f46
--- /dev/null
+++ b/arch/riscv/kvm/vmid.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/cpumask.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/kvm_host.h>
+#include <asm/csr.h>
+
+static unsigned long vmid_version = 1;
+static unsigned long vmid_next;
+static unsigned long vmid_bits;
+static DEFINE_SPINLOCK(vmid_lock);
+
+void kvm_riscv_stage2_vmid_detect(void)
+{
+	unsigned long old;
+
+	/* Figure-out number of VMID bits in HW */
+	old = csr_read(CSR_HGATP);
+	csr_write(CSR_HGATP, old | HGATP_VMID_MASK);
+	vmid_bits = csr_read(CSR_HGATP);
+	vmid_bits = (vmid_bits & HGATP_VMID_MASK) >> HGATP_VMID_SHIFT;
+	vmid_bits = fls_long(vmid_bits);
+	csr_write(CSR_HGATP, old);
+
+	/* We polluted local TLB so flush all guest TLB */
+	__kvm_riscv_hfence_gvma_all();
+
+	/* We don't use VMID bits if they are not sufficient */
+	if ((1UL << vmid_bits) < num_possible_cpus())
+		vmid_bits = 0;
+}
+
+unsigned long kvm_riscv_stage2_vmid_bits(void)
+{
+	return vmid_bits;
+}
+
+int kvm_riscv_stage2_vmid_init(struct kvm *kvm)
+{
+	/* Mark the initial VMID and VMID version invalid */
+	kvm->arch.vmid.vmid_version = 0;
+	kvm->arch.vmid.vmid = 0;
+
+	return 0;
+}
+
+static void local_guest_tlb_flush_all(void *info)
+{
+	__kvm_riscv_hfence_gvma_all();
+}
+
+bool kvm_riscv_stage2_vmid_ver_changed(struct kvm_vmid *vmid)
+{
+	if (!vmid_bits)
+		return false;
+
+	return unlikely(READ_ONCE(vmid->vmid_version) !=
+			READ_ONCE(vmid_version));
+}
+
+void kvm_riscv_stage2_vmid_update(struct kvm_vcpu *vcpu)
+{
+	int i;
+	struct kvm_vcpu *v;
+	struct kvm_vmid *vmid = &vcpu->kvm->arch.vmid;
+
+	if (!kvm_riscv_stage2_vmid_ver_changed(vmid))
+		return;
+
+	spin_lock(&vmid_lock);
+
+	/*
+	 * We need to re-check the vmid_version here to ensure that if
+	 * another vcpu already allocated a valid vmid for this vm.
+	 */
+	if (!kvm_riscv_stage2_vmid_ver_changed(vmid)) {
+		spin_unlock(&vmid_lock);
+		return;
+	}
+
+	/* First user of a new VMID version? */
+	if (unlikely(vmid_next == 0)) {
+		WRITE_ONCE(vmid_version, READ_ONCE(vmid_version) + 1);
+		vmid_next = 1;
+
+		/*
+		 * We ran out of VMIDs so we increment vmid_version and
+		 * start assigning VMIDs from 1.
+		 *
+		 * This also means existing VMIDs assignement to all Guest
+		 * instances is invalid and we have force VMID re-assignement
+		 * for all Guest instances. The Guest instances that were not
+		 * running will automatically pick-up new VMIDs because will
+		 * call kvm_riscv_stage2_vmid_update() whenever they enter
+		 * in-kernel run loop. For Guest instances that are already
+		 * running, we force VM exits on all host CPUs using IPI and
+		 * flush all Guest TLBs.
+		 */
+		smp_call_function_many(cpu_online_mask,
+				       local_guest_tlb_flush_all, NULL, true);
+	}
+
+	vmid->vmid = vmid_next;
+	vmid_next++;
+	vmid_next &= (1 << vmid_bits) - 1;
+
+	WRITE_ONCE(vmid->vmid_version, READ_ONCE(vmid_version));
+
+	spin_unlock(&vmid_lock);
+
+	/* Request stage2 page table update for all VCPUs */
+	kvm_for_each_vcpu(i, v, vcpu->kvm)
+		kvm_make_request(KVM_REQ_UPDATE_HGATP, v);
+}
-- 
2.17.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v7 13/21] RISC-V: KVM: Implement stage2 page table programming

[Anup Patel]

This patch implements all required functions for programming
the stage2 page table for each Guest/VM.

At high-level, the flow of stage2 related functions is similar
from KVM ARM/ARM64 implementation but the stage2 page table
format is quite different for KVM RISC-V.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/riscv/include/asm/kvm_host.h     |  10 +
 arch/riscv/include/asm/pgtable-bits.h |   1 +
 arch/riscv/kvm/mmu.c                  | 643 +++++++++++++++++++++++++-
 3 files changed, 644 insertions(+), 10 deletions(-)

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 8aaf22a900be..bc27f664b443 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -73,6 +73,13 @@ struct kvm_mmio_decode {
 	int return_handled;
 };
 
+#define KVM_MMU_PAGE_CACHE_NR_OBJS	32
+
+struct kvm_mmu_page_cache {
+	int nobjs;
+	void *objects[KVM_MMU_PAGE_CACHE_NR_OBJS];
+};
+
 struct kvm_cpu_context {
 	unsigned long zero;
 	unsigned long ra;
@@ -164,6 +171,9 @@ struct kvm_vcpu_arch {
 	/* MMIO instruction details */
 	struct kvm_mmio_decode mmio_decode;
 
+	/* Cache pages needed to program page tables with spinlock held */
+	struct kvm_mmu_page_cache mmu_page_cache;
+
 	/* VCPU power-off state */
 	bool power_off;
 
diff --git a/arch/riscv/include/asm/pgtable-bits.h b/arch/riscv/include/asm/pgtable-bits.h
index bbaeb5d35842..be49d62fcc2b 100644
--- a/arch/riscv/include/asm/pgtable-bits.h
+++ b/arch/riscv/include/asm/pgtable-bits.h
@@ -26,6 +26,7 @@
 
 #define _PAGE_SPECIAL   _PAGE_SOFT
 #define _PAGE_TABLE     _PAGE_PRESENT
+#define _PAGE_LEAF      (_PAGE_READ | _PAGE_WRITE | _PAGE_EXEC)
 
 /*
  * _PAGE_PROT_NONE is set on not-present pages (and ignored by the hardware) to
diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
index 2b965f9aac07..590669290139 100644
--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c
@@ -18,6 +18,438 @@
 #include <asm/page.h>
 #include <asm/pgtable.h>
 
+#ifdef CONFIG_64BIT
+#define stage2_have_pmd		true
+#define stage2_gpa_size		((phys_addr_t)(1ULL << 39))
+#define stage2_cache_min_pages	2
+#else
+#define pmd_index(x)		0
+#define pfn_pmd(x, y)		({ pmd_t __x = { 0 }; __x; })
+#define stage2_have_pmd		false
+#define stage2_gpa_size		((phys_addr_t)(1ULL << 32))
+#define stage2_cache_min_pages	1
+#endif
+
+static int stage2_cache_topup(struct kvm_mmu_page_cache *pcache,
+			      int min, int max)
+{
+	void *page;
+
+	BUG_ON(max > KVM_MMU_PAGE_CACHE_NR_OBJS);
+	if (pcache->nobjs >= min)
+		return 0;
+	while (pcache->nobjs < max) {
+		page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+		if (!page)
+			return -ENOMEM;
+		pcache->objects[pcache->nobjs++] = page;
+	}
+
+	return 0;
+}
+
+static void stage2_cache_flush(struct kvm_mmu_page_cache *pcache)
+{
+	while (pcache && pcache->nobjs)
+		free_page((unsigned long)pcache->objects[--pcache->nobjs]);
+}
+
+static void *stage2_cache_alloc(struct kvm_mmu_page_cache *pcache)
+{
+	void *p;
+
+	if (!pcache)
+		return NULL;
+
+	BUG_ON(!pcache->nobjs);
+	p = pcache->objects[--pcache->nobjs];
+
+	return p;
+}
+
+struct local_guest_tlb_info {
+	struct kvm_vmid *vmid;
+	gpa_t addr;
+};
+
+static void local_guest_tlb_flush_vmid_gpa(void *info)
+{
+	struct local_guest_tlb_info *infop = info;
+
+	__kvm_riscv_hfence_gvma_vmid_gpa(READ_ONCE(infop->vmid->vmid_version),
+					 infop->addr);
+}
+
+static void stage2_remote_tlb_flush(struct kvm *kvm, gpa_t addr)
+{
+	struct local_guest_tlb_info info;
+	struct kvm_vmid *vmid = &kvm->arch.vmid;
+
+	/*
+	 * Ideally, we should have a SBI call OR some remote TLB instruction
+	 * but we don't have it so we explicitly flush TLBs using IPIs.
+	 *
+	 * TODO: Instead of cpu_online_mask, we should only target CPUs
+	 * where the Guest/VM is running.
+	 */
+	info.vmid = vmid;
+	info.addr = addr;
+	preempt_disable();
+	smp_call_function_many(cpu_online_mask,
+			       local_guest_tlb_flush_vmid_gpa, &info, true);
+	preempt_enable();
+}
+
+static int stage2_set_pgd(struct kvm *kvm, gpa_t addr, const pgd_t *new_pgd)
+{
+	pgd_t *pgdp = &kvm->arch.pgd[pgd_index(addr)];
+
+	*pgdp = *new_pgd;
+	if (pgd_val(*pgdp) & _PAGE_LEAF)
+		stage2_remote_tlb_flush(kvm, addr);
+
+	return 0;
+}
+
+static int stage2_set_pmd(struct kvm *kvm, struct kvm_mmu_page_cache *pcache,
+			  gpa_t addr, const pmd_t *new_pmd)
+{
+	int rc;
+	pmd_t *pmdp;
+	pgd_t new_pgd;
+	pgd_t *pgdp = &kvm->arch.pgd[pgd_index(addr)];
+
+	if (!pgd_val(*pgdp)) {
+		pmdp = stage2_cache_alloc(pcache);
+		if (!pmdp)
+			return -ENOMEM;
+		new_pgd = pfn_pgd(PFN_DOWN(__pa(pmdp)), __pgprot(_PAGE_TABLE));
+		rc = stage2_set_pgd(kvm, addr, &new_pgd);
+		if (rc)
+			return rc;
+	}
+
+	if (pgd_val(*pgdp) & _PAGE_LEAF)
+		return -EEXIST;
+
+	pmdp = (void *)pgd_page_vaddr(*pgdp);
+	pmdp = &pmdp[pmd_index(addr)];
+
+	*pmdp = *new_pmd;
+	if (pmd_val(*pmdp) & _PAGE_LEAF)
+		stage2_remote_tlb_flush(kvm, addr);
+
+	return 0;
+}
+
+static int stage2_set_pte(struct kvm *kvm,
+			  struct kvm_mmu_page_cache *pcache,
+			  gpa_t addr, const pte_t *new_pte)
+{
+	int rc;
+	pte_t *ptep;
+	pmd_t new_pmd;
+	pmd_t *pmdp;
+	pgd_t new_pgd;
+	pgd_t *pgdp = &kvm->arch.pgd[pgd_index(addr)];
+
+	if (!pgd_val(*pgdp)) {
+		pmdp = stage2_cache_alloc(pcache);
+		if (!pmdp)
+			return -ENOMEM;
+		new_pgd = pfn_pgd(PFN_DOWN(__pa(pmdp)), __pgprot(_PAGE_TABLE));
+		rc = stage2_set_pgd(kvm, addr, &new_pgd);
+		if (rc)
+			return rc;
+	}
+
+	if (pgd_val(*pgdp) & _PAGE_LEAF)
+		return -EEXIST;
+
+	if (stage2_have_pmd) {
+		pmdp = (void *)pgd_page_vaddr(*pgdp);
+		pmdp = &pmdp[pmd_index(addr)];
+		if (!pmd_present(*pmdp)) {
+			ptep = stage2_cache_alloc(pcache);
+			if (!ptep)
+				return -ENOMEM;
+			new_pmd = pfn_pmd(PFN_DOWN(__pa(ptep)),
+					  __pgprot(_PAGE_TABLE));
+			rc = stage2_set_pmd(kvm, pcache, addr, &new_pmd);
+			if (rc)
+				return rc;
+		}
+
+		if (pmd_val(*pmdp) & _PAGE_LEAF)
+			return -EEXIST;
+
+		ptep = (void *)pmd_page_vaddr(*pmdp);
+	} else {
+		ptep = (void *)pgd_page_vaddr(*pgdp);
+	}
+
+	ptep = &ptep[pte_index(addr)];
+
+	*ptep = *new_pte;
+	if (pte_val(*ptep) & _PAGE_LEAF)
+		stage2_remote_tlb_flush(kvm, addr);
+
+	return 0;
+}
+
+static int stage2_map_page(struct kvm *kvm,
+			   struct kvm_mmu_page_cache *pcache,
+			   gpa_t gpa, phys_addr_t hpa,
+			   unsigned long page_size, pgprot_t prot)
+{
+	pte_t new_pte;
+	pmd_t new_pmd;
+	pgd_t new_pgd;
+
+	if (page_size == PAGE_SIZE) {
+		new_pte = pfn_pte(PFN_DOWN(hpa), prot);
+		return stage2_set_pte(kvm, pcache, gpa, &new_pte);
+	}
+
+	if (stage2_have_pmd && page_size == PMD_SIZE) {
+		new_pmd = pfn_pmd(PFN_DOWN(hpa), prot);
+		return stage2_set_pmd(kvm, pcache, gpa, &new_pmd);
+	}
+
+	if (page_size == PGDIR_SIZE) {
+		new_pgd = pfn_pgd(PFN_DOWN(hpa), prot);
+		return stage2_set_pgd(kvm, gpa, &new_pgd);
+	}
+
+	return -EINVAL;
+}
+
+enum stage2_op {
+	STAGE2_OP_NOP = 0,	/* Nothing */
+	STAGE2_OP_CLEAR,	/* Clear/Unmap */
+	STAGE2_OP_WP,		/* Write-protect */
+};
+
+static void stage2_op_pte(struct kvm *kvm, gpa_t addr, pte_t *ptep,
+			  enum stage2_op op)
+{
+	BUG_ON(addr & (PAGE_SIZE - 1));
+
+	if (!pte_present(*ptep))
+		return;
+
+	if (op == STAGE2_OP_CLEAR)
+		set_pte(ptep, __pte(0));
+	else if (op == STAGE2_OP_WP)
+		set_pte(ptep, __pte(pte_val(*ptep) & ~_PAGE_WRITE));
+	stage2_remote_tlb_flush(kvm, addr);
+}
+
+static void stage2_op_pmd(struct kvm *kvm, gpa_t addr, pmd_t *pmdp,
+			  enum stage2_op op)
+{
+	int i;
+	pte_t *ptep;
+
+	BUG_ON(addr & (PMD_SIZE - 1));
+
+	if (!pmd_present(*pmdp))
+		return;
+
+	if (pmd_val(*pmdp) & _PAGE_LEAF)
+		ptep = NULL;
+	else
+		ptep = (pte_t *)pmd_page_vaddr(*pmdp);
+
+	if (op == STAGE2_OP_CLEAR)
+		set_pmd(pmdp, __pmd(0));
+
+	if (ptep) {
+		for (i = 0; i < PTRS_PER_PTE; i++)
+			stage2_op_pte(kvm, addr + i * PAGE_SIZE, &ptep[i], op);
+		if (op == STAGE2_OP_CLEAR)
+			put_page(virt_to_page(ptep));
+	} else {
+		if (op == STAGE2_OP_WP)
+			set_pmd(pmdp, __pmd(pmd_val(*pmdp) & ~_PAGE_WRITE));
+		stage2_remote_tlb_flush(kvm, addr);
+	}
+}
+
+static void stage2_op_pgd(struct kvm *kvm, gpa_t addr, pgd_t *pgdp,
+			  enum stage2_op op)
+{
+	int i;
+	pte_t *ptep;
+	pmd_t *pmdp;
+
+	BUG_ON(addr & (PGDIR_SIZE - 1));
+
+	if (!pgd_val(*pgdp))
+		return;
+
+	ptep = NULL;
+	pmdp = NULL;
+	if (!(pgd_val(*pgdp) & _PAGE_LEAF)) {
+		if (stage2_have_pmd)
+			pmdp = (pmd_t *)pgd_page_vaddr(*pgdp);
+		else
+			ptep = (pte_t *)pgd_page_vaddr(*pgdp);
+	}
+
+	if (op == STAGE2_OP_CLEAR)
+		set_pgd(pgdp, __pgd(0));
+
+	if (pmdp) {
+		for (i = 0; i < PTRS_PER_PMD; i++)
+			stage2_op_pmd(kvm, addr + i * PMD_SIZE, &pmdp[i], op);
+		if (op == STAGE2_OP_CLEAR)
+			put_page(virt_to_page(pmdp));
+	} else if (ptep) {
+		for (i = 0; i < PTRS_PER_PTE; i++)
+			stage2_op_pte(kvm, addr + i * PAGE_SIZE, &ptep[i], op);
+		if (op == STAGE2_OP_CLEAR)
+			put_page(virt_to_page(ptep));
+	} else {
+		if (op == STAGE2_OP_WP)
+			set_pgd(pgdp, __pgd(pgd_val(*pgdp) & ~_PAGE_WRITE));
+		stage2_remote_tlb_flush(kvm, addr);
+	}
+}
+
+static void stage2_unmap_range(struct kvm *kvm, gpa_t start, gpa_t size)
+{
+	pmd_t *pmdp;
+	pte_t *ptep;
+	pgd_t *pgdp;
+	gpa_t addr = start, end = start + size;
+
+	while (addr < end) {
+		pgdp = &kvm->arch.pgd[pgd_index(addr)];
+		if (!pgd_val(*pgdp)) {
+			addr += PGDIR_SIZE;
+			continue;
+		} else if (!(addr & (PGDIR_SIZE - 1)) &&
+			  ((end - addr) >= PGDIR_SIZE)) {
+			stage2_op_pgd(kvm, addr, pgdp, STAGE2_OP_CLEAR);
+			addr += PGDIR_SIZE;
+			continue;
+		}
+
+		if (stage2_have_pmd) {
+			pmdp = (pmd_t *)pgd_page_vaddr(*pgdp);
+			if (!pmd_present(*pmdp)) {
+				addr += PMD_SIZE;
+				continue;
+			} else if (!(addr & (PMD_SIZE - 1)) &&
+				   ((end - addr) >= PMD_SIZE)) {
+				stage2_op_pmd(kvm, addr, pmdp,
+					      STAGE2_OP_CLEAR);
+				addr += PMD_SIZE;
+				continue;
+			}
+			ptep = (pte_t *)pmd_page_vaddr(*pmdp);
+		} else {
+			ptep = (pte_t *)pgd_page_vaddr(*pgdp);
+		}
+
+		stage2_op_pte(kvm, addr, ptep, STAGE2_OP_CLEAR);
+		addr += PAGE_SIZE;
+	}
+}
+
+static void stage2_wp_range(struct kvm *kvm, gpa_t start, gpa_t end)
+{
+	pmd_t *pmdp;
+	pte_t *ptep;
+	pgd_t *pgdp;
+	gpa_t addr = start;
+
+	while (addr < end) {
+		pgdp = &kvm->arch.pgd[pgd_index(addr)];
+		if (!pgd_val(*pgdp)) {
+			addr += PGDIR_SIZE;
+			continue;
+		} else if (!(addr & (PGDIR_SIZE - 1)) &&
+			   ((end - addr) >= PGDIR_SIZE)) {
+			stage2_op_pgd(kvm, addr, pgdp, STAGE2_OP_WP);
+			addr += PGDIR_SIZE;
+			continue;
+		}
+
+		if (stage2_have_pmd) {
+			pmdp = (pmd_t *)pgd_page_vaddr(*pgdp);
+			if (!pmd_present(*pmdp)) {
+				addr += PMD_SIZE;
+				continue;
+			} else if (!(addr & (PMD_SIZE - 1)) &&
+				   ((end - addr) >= PMD_SIZE)) {
+				stage2_op_pmd(kvm, addr, pmdp, STAGE2_OP_WP);
+				addr += PMD_SIZE;
+				continue;
+			}
+			ptep = (pte_t *)pmd_page_vaddr(*pmdp);
+		} else {
+			ptep = (pte_t *)pgd_page_vaddr(*pgdp);
+		}
+
+		stage2_op_pte(kvm, addr, ptep, STAGE2_OP_WP);
+		addr += PAGE_SIZE;
+	}
+}
+
+void stage2_wp_memory_region(struct kvm *kvm, int slot)
+{
+	struct kvm_memslots *slots = kvm_memslots(kvm);
+	struct kvm_memory_slot *memslot = id_to_memslot(slots, slot);
+	phys_addr_t start = memslot->base_gfn << PAGE_SHIFT;
+	phys_addr_t end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT;
+
+	spin_lock(&kvm->mmu_lock);
+	stage2_wp_range(kvm, start, end);
+	spin_unlock(&kvm->mmu_lock);
+	kvm_flush_remote_tlbs(kvm);
+}
+
+int stage2_ioremap(struct kvm *kvm, gpa_t gpa, phys_addr_t hpa,
+		   unsigned long size, bool writable)
+{
+	pte_t pte;
+	int ret = 0;
+	unsigned long pfn;
+	phys_addr_t addr, end;
+	struct kvm_mmu_page_cache pcache = { 0, };
+
+	end = (gpa + size + PAGE_SIZE - 1) & PAGE_MASK;
+	pfn = __phys_to_pfn(hpa);
+
+	for (addr = gpa; addr < end; addr += PAGE_SIZE) {
+		pte = pfn_pte(pfn, PAGE_KERNEL);
+
+		if (!writable)
+			pte = pte_wrprotect(pte);
+
+		ret = stage2_cache_topup(&pcache,
+					 stage2_cache_min_pages,
+					 KVM_MMU_PAGE_CACHE_NR_OBJS);
+		if (ret)
+			goto out;
+
+		spin_lock(&kvm->mmu_lock);
+		ret = stage2_set_pte(kvm, &pcache, addr, &pte);
+		spin_unlock(&kvm->mmu_lock);
+		if (ret)
+			goto out;
+
+		pfn++;
+	}
+
+out:
+	stage2_cache_flush(&pcache);
+	return ret;
+
+}
+
 void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free,
 			   struct kvm_memory_slot *dont)
 {
@@ -35,7 +467,7 @@ void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen)
 
 void kvm_arch_flush_shadow_all(struct kvm *kvm)
 {
-	/* TODO: */
+	kvm_riscv_stage2_free_pgd(kvm);
 }
 
 void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
@@ -49,7 +481,13 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
 				const struct kvm_memory_slot *new,
 				enum kvm_mr_change change)
 {
-	/* TODO: */
+	/*
+	 * At this point memslot has been committed and there is an
+	 * allocated dirty_bitmap[], dirty pages will be be tracked while the
+	 * memory slot is write protected.
+	 */
+	if (change != KVM_MR_DELETE && mem->flags & KVM_MEM_LOG_DIRTY_PAGES)
+		stage2_wp_memory_region(kvm, mem->slot);
 }
 
 int kvm_arch_prepare_memory_region(struct kvm *kvm,
@@ -57,34 +495,219 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 				const struct kvm_userspace_memory_region *mem,
 				enum kvm_mr_change change)
 {
-	/* TODO: */
-	return 0;
+	hva_t hva = mem->userspace_addr;
+	hva_t reg_end = hva + mem->memory_size;
+	bool writable = !(mem->flags & KVM_MEM_READONLY);
+	int ret = 0;
+
+	if (change != KVM_MR_CREATE && change != KVM_MR_MOVE &&
+			change != KVM_MR_FLAGS_ONLY)
+		return 0;
+
+	/*
+	 * Prevent userspace from creating a memory region outside of the GPA
+	 * space addressable by the KVM guest GPA space.
+	 */
+	if ((memslot->base_gfn + memslot->npages) >=
+	    (stage2_gpa_size >> PAGE_SHIFT))
+		return -EFAULT;
+
+	down_read(&current->mm->mmap_sem);
+
+	/*
+	 * A memory region could potentially cover multiple VMAs, and
+	 * any holes between them, so iterate over all of them to find
+	 * out if we can map any of them right now.
+	 *
+	 *     +--------------------------------------------+
+	 * +---------------+----------------+   +----------------+
+	 * |   : VMA 1     |      VMA 2     |   |    VMA 3  :    |
+	 * +---------------+----------------+   +----------------+
+	 *     |               memory region                |
+	 *     +--------------------------------------------+
+	 */
+	do {
+		struct vm_area_struct *vma = find_vma(current->mm, hva);
+		hva_t vm_start, vm_end;
+
+		if (!vma || vma->vm_start >= reg_end)
+			break;
+
+		/*
+		 * Mapping a read-only VMA is only allowed if the
+		 * memory region is configured as read-only.
+		 */
+		if (writable && !(vma->vm_flags & VM_WRITE)) {
+			ret = -EPERM;
+			break;
+		}
+
+		/* Take the intersection of this VMA with the memory region */
+		vm_start = max(hva, vma->vm_start);
+		vm_end = min(reg_end, vma->vm_end);
+
+		if (vma->vm_flags & VM_PFNMAP) {
+			gpa_t gpa = mem->guest_phys_addr +
+				    (vm_start - mem->userspace_addr);
+			phys_addr_t pa;
+
+			pa = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT;
+			pa += vm_start - vma->vm_start;
+
+			/* IO region dirty page logging not allowed */
+			if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES) {
+				ret = -EINVAL;
+				goto out;
+			}
+
+			ret = stage2_ioremap(kvm, gpa, pa,
+					     vm_end - vm_start, writable);
+			if (ret)
+				break;
+		}
+		hva = vm_end;
+	} while (hva < reg_end);
+
+	if (change == KVM_MR_FLAGS_ONLY)
+		goto out;
+
+	spin_lock(&kvm->mmu_lock);
+	if (ret)
+		stage2_unmap_range(kvm, mem->guest_phys_addr,
+				   mem->memory_size);
+	spin_unlock(&kvm->mmu_lock);
+
+out:
+	up_read(&current->mm->mmap_sem);
+	return ret;
 }
 
 int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned long hva,
 			 bool is_write)
 {
-	/* TODO: */
-	return 0;
+	int ret;
+	short lsb;
+	kvm_pfn_t hfn;
+	bool writeable;
+	gfn_t gfn = gpa >> PAGE_SHIFT;
+	struct vm_area_struct *vma;
+	struct kvm *kvm = vcpu->kvm;
+	struct kvm_mmu_page_cache *pcache = &vcpu->arch.mmu_page_cache;
+	unsigned long vma_pagesize;
+
+	down_read(&current->mm->mmap_sem);
+
+	vma = find_vma_intersection(current->mm, hva, hva + 1);
+	if (unlikely(!vma)) {
+		kvm_err("Failed to find VMA for hva 0x%lx\n", hva);
+		up_read(&current->mm->mmap_sem);
+		return -EFAULT;
+	}
+
+	vma_pagesize = vma_kernel_pagesize(vma);
+
+	up_read(&current->mm->mmap_sem);
+
+	if (vma_pagesize != PGDIR_SIZE &&
+	    vma_pagesize != PMD_SIZE &&
+	    vma_pagesize != PAGE_SIZE) {
+		kvm_err("Invalid VMA page size 0x%lx\n", vma_pagesize);
+		return -EFAULT;
+	}
+
+	/* We need minimum second+third level pages */
+	ret = stage2_cache_topup(pcache, stage2_cache_min_pages,
+				 KVM_MMU_PAGE_CACHE_NR_OBJS);
+	if (ret) {
+		kvm_err("Failed to topup stage2 cache\n");
+		return ret;
+	}
+
+	hfn = gfn_to_pfn_prot(kvm, gfn, is_write, &writeable);
+	if (hfn == KVM_PFN_ERR_HWPOISON) {
+		if (is_vm_hugetlb_page(vma))
+			lsb = huge_page_shift(hstate_vma(vma));
+		else
+			lsb = PAGE_SHIFT;
+
+		send_sig_mceerr(BUS_MCEERR_AR, (void __user *)hva,
+				lsb, current);
+		return 0;
+	}
+	if (is_error_noslot_pfn(hfn))
+		return -EFAULT;
+	if (!writeable && is_write)
+		return -EPERM;
+
+	spin_lock(&kvm->mmu_lock);
+
+	if (writeable) {
+		kvm_set_pfn_dirty(hfn);
+		ret = stage2_map_page(kvm, pcache, gpa, hfn << PAGE_SHIFT,
+				      vma_pagesize, PAGE_WRITE_EXEC);
+	} else {
+		ret = stage2_map_page(kvm, pcache, gpa, hfn << PAGE_SHIFT,
+				      vma_pagesize, PAGE_READ_EXEC);
+	}
+
+	if (ret)
+		kvm_err("Failed to map in stage2\n");
+
+	spin_unlock(&kvm->mmu_lock);
+	kvm_set_pfn_accessed(hfn);
+	kvm_release_pfn_clean(hfn);
+	return ret;
 }
 
 void kvm_riscv_stage2_flush_cache(struct kvm_vcpu *vcpu)
 {
-	/* TODO: */
+	stage2_cache_flush(&vcpu->arch.mmu_page_cache);
 }
 
 int kvm_riscv_stage2_alloc_pgd(struct kvm *kvm)
 {
-	/* TODO: */
+	if (kvm->arch.pgd != NULL) {
+		kvm_err("kvm_arch already initialized?\n");
+		return -EINVAL;
+	}
+
+	kvm->arch.pgd = alloc_pages_exact(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO);
+	if (!kvm->arch.pgd)
+		return -ENOMEM;
+	kvm->arch.pgd_phys = virt_to_phys(kvm->arch.pgd);
+
 	return 0;
 }
 
 void kvm_riscv_stage2_free_pgd(struct kvm *kvm)
 {
-	/* TODO: */
+	void *pgd = NULL;
+
+	spin_lock(&kvm->mmu_lock);
+	if (kvm->arch.pgd) {
+		stage2_unmap_range(kvm, 0UL, stage2_gpa_size);
+		pgd = READ_ONCE(kvm->arch.pgd);
+		kvm->arch.pgd = NULL;
+		kvm->arch.pgd_phys = 0;
+	}
+	spin_unlock(&kvm->mmu_lock);
+
+	/* Free the HW pgd, one page at a time */
+	if (pgd)
+		free_pages_exact(pgd, PAGE_SIZE);
 }
 
 void kvm_riscv_stage2_update_hgatp(struct kvm_vcpu *vcpu)
 {
-	/* TODO: */
+	unsigned long hgatp = HGATP_MODE;
+	struct kvm_arch *k = &vcpu->kvm->arch;
+
+	hgatp |= (READ_ONCE(k->vmid.vmid) << HGATP_VMID_SHIFT) &
+		 HGATP_VMID_MASK;
+	hgatp |= (k->pgd_phys >> PAGE_SHIFT) & HGATP_PPN;
+
+	csr_write(CSR_HGATP, hgatp);
+
+	if (!kvm_riscv_stage2_vmid_bits())
+		__kvm_riscv_hfence_gvma_all();
 }
-- 
2.17.1


_______________________________________________
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linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

[PATCH v7 14/21] RISC-V: KVM: Implement MMU notifiers

[Anup Patel]

This patch implements MMU notifiers for KVM RISC-V so that Guest
physical address space is in-sync with Host physical address space.

This will allow swapping, page migration, etc to work transparently
with KVM RISC-V.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
 arch/riscv/include/asm/kvm_host.h |   7 ++
 arch/riscv/kvm/Kconfig            |   1 +
 arch/riscv/kvm/mmu.c              | 200 +++++++++++++++++++++++++++++-
 arch/riscv/kvm/vm.c               |   1 +
 4 files changed, 208 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index bc27f664b443..79ceb2aa8ae6 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -193,6 +193,13 @@ static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {}
 int kvm_riscv_setup_vsip(void);
 void kvm_riscv_cleanup_vsip(void);
 
+#define KVM_ARCH_WANT_MMU_NOTIFIER
+int kvm_unmap_hva_range(struct kvm *kvm,
+			unsigned long start, unsigned long end);
+int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte);
+int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end);
+int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);
+
 void __kvm_riscv_hfence_gvma_vmid_gpa(unsigned long vmid,
 				      unsigned long gpa);
 void __kvm_riscv_hfence_gvma_vmid(unsigned long vmid);
diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
index 35fd30d0e432..002e14ee37f6 100644
--- a/arch/riscv/kvm/Kconfig
+++ b/arch/riscv/kvm/Kconfig
@@ -20,6 +20,7 @@ if VIRTUALIZATION
 config KVM
 	tristate "Kernel-based Virtual Machine (KVM) support"
 	depends on OF
+	select MMU_NOTIFIER
 	select PREEMPT_NOTIFIERS
 	select ANON_INODES
 	select KVM_MMIO
diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
index 590669290139..d8a692d3e640 100644
--- a/arch/riscv/kvm/mmu.c
+++ b/arch/riscv/kvm/mmu.c
@@ -67,6 +67,66 @@ static void *stage2_cache_alloc(struct kvm_mmu_page_cache *pcache)
 	return p;
 }
 
+static int stage2_pgdp_test_and_clear_young(pgd_t *pgd)
+{
+	return ptep_test_and_clear_young(NULL, 0, (pte_t *)pgd);
+}
+
+static int stage2_pmdp_test_and_clear_young(pmd_t *pmd)
+{
+	return ptep_test_and_clear_young(NULL, 0, (pte_t *)pmd);
+}
+
+static int stage2_ptep_test_and_clear_young(pte_t *pte)
+{
+	return ptep_test_and_clear_young(NULL, 0, pte);
+}
+
+static bool stage2_get_leaf_entry(struct kvm *kvm, gpa_t addr,
+				  pgd_t **pgdpp, pmd_t **pmdpp, pte_t **ptepp)
+{
+	pgd_t *pgdp;
+	pmd_t *pmdp;
+	pte_t *ptep;
+
+	*pgdpp = NULL;
+	*pmdpp = NULL;
+	*ptepp = NULL;
+
+	pgdp = &kvm->arch.pgd[pgd_index(addr)];
+	if (!pgd_val(*pgdp))
+		return false;
+	if (pgd_val(*pgdp) & _PAGE_LEAF) {
+		*pgdpp = pgdp;
+		return true;
+	}
+
+	if (stage2_have_pmd) {
+		pmdp = (void *)pgd_page_vaddr(*pgdp);
+		pmdp = &pmdp[pmd_index(addr)];
+		if (!pmd_present(*pmdp))
+			return false;
+		if (pmd_val(*pmdp) & _PAGE_LEAF) {
+			*pmdpp = pmdp;
+			return true;
+		}
+
+		ptep = (void *)pmd_page_vaddr(*pmdp);
+	} else {
+		ptep = (void *)pgd_page_vaddr(*pgdp);
+	}
+
+	ptep = &ptep[pte_index(addr)];
+	if (!pte_present(*ptep))
+		return false;
+	if (pte_val(*ptep) & _PAGE_LEAF) {
+		*ptepp = ptep;
+		return true;
+	}
+
+	return false;
+}
+
 struct local_guest_tlb_info {
 	struct kvm_vmid *vmid;
 	gpa_t addr;
@@ -450,6 +510,38 @@ int stage2_ioremap(struct kvm *kvm, gpa_t gpa, phys_addr_t hpa,
 
 }
 
+static int handle_hva_to_gpa(struct kvm *kvm,
+			     unsigned long start,
+			     unsigned long end,
+			     int (*handler)(struct kvm *kvm,
+					    gpa_t gpa, u64 size,
+					    void *data),
+			     void *data)
+{
+	struct kvm_memslots *slots;
+	struct kvm_memory_slot *memslot;
+	int ret = 0;
+
+	slots = kvm_memslots(kvm);
+
+	/* we only care about the pages that the guest sees */
+	kvm_for_each_memslot(memslot, slots) {
+		unsigned long hva_start, hva_end;
+		gfn_t gpa;
+
+		hva_start = max(start, memslot->userspace_addr);
+		hva_end = min(end, memslot->userspace_addr +
+					(memslot->npages << PAGE_SHIFT));
+		if (hva_start >= hva_end)
+			continue;
+
+		gpa = hva_to_gfn_memslot(hva_start, memslot) << PAGE_SHIFT;
+		ret |= handler(kvm, gpa, (u64)(hva_end - hva_start), data);
+	}
+
+	return ret;
+}
+
 void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free,
 			   struct kvm_memory_slot *dont)
 {
@@ -582,6 +674,106 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 	return ret;
 }
 
+static int kvm_unmap_hva_handler(struct kvm *kvm,
+				 gpa_t gpa, u64 size, void *data)
+{
+	stage2_unmap_range(kvm, gpa, size);
+	return 0;
+}
+
+int kvm_unmap_hva_range(struct kvm *kvm,
+			unsigned long start, unsigned long end)
+{
+	if (!kvm->arch.pgd)
+		return 0;
+
+	handle_hva_to_gpa(kvm, start, end,
+			  &kvm_unmap_hva_handler, NULL);
+	return 0;
+}
+
+static int kvm_set_spte_handler(struct kvm *kvm,
+				gpa_t gpa, u64 size, void *data)
+{
+	pte_t *pte = (pte_t *)data;
+
+	WARN_ON(size != PAGE_SIZE);
+	stage2_set_pte(kvm, NULL, gpa, pte);
+
+	return 0;
+}
+
+int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
+{
+	unsigned long end = hva + PAGE_SIZE;
+	kvm_pfn_t pfn = pte_pfn(pte);
+	pte_t stage2_pte;
+
+	if (!kvm->arch.pgd)
+		return 0;
+
+	stage2_pte = pfn_pte(pfn, PAGE_WRITE_EXEC);
+	handle_hva_to_gpa(kvm, hva, end,
+			  &kvm_set_spte_handler, &stage2_pte);
+
+	return 0;
+}
+
+static int kvm_age_hva_handler(struct kvm *kvm,
+				gpa_t gpa, u64 size, void *data)
+{
+	pgd_t *pgd;
+	pmd_t *pmd;
+	pte_t *pte;
+
+	WARN_ON(size != PAGE_SIZE && size != PMD_SIZE && size != PGDIR_SIZE);
+	if (!stage2_get_leaf_entry(kvm, gpa, &pgd, &pmd, &pte))
+		return 0;
+
+	if (pgd)
+		return stage2_pgdp_test_and_clear_young(pgd);
+	else if (pmd)
+		return stage2_pmdp_test_and_clear_young(pmd);
+	else
+		return stage2_ptep_test_and_clear_young(pte);
+}
+
+int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)
+{
+	if (!kvm->arch.pgd)
+		return 0;
+
+	return handle_hva_to_gpa(kvm, start, end, kvm_age_hva_handler, NULL);
+}
+
+static int kvm_test_age_hva_handler(struct kvm *kvm,
+				    gpa_t gpa, u64 size, void *data)
+{
+	pgd_t *pgd;
+	pmd_t *pmd;
+	pte_t *pte;
+
+	WARN_ON(size != PAGE_SIZE && size != PMD_SIZE);
+	if (!stage2_get_leaf_entry(kvm, gpa, &pgd, &pmd, &pte))
+		return 0;
+
+	if (pgd)
+		return pte_young(*((pte_t *)pgd));
+	else if (pmd)
+		return pte_young(*((pte_t *)pmd));
+	else
+		return pte_young(*pte);
+}
+
+int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
+{
+	if (!kvm->arch.pgd)
+		return 0;
+
+	return handle_hva_to_gpa(kvm, hva, hva,
+				 kvm_test_age_hva_handler, NULL);
+}
+
 int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned long hva,
 			 bool is_write)
 {
@@ -593,7 +785,7 @@ int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned long hva,
 	struct vm_area_struct *vma;
 	struct kvm *kvm = vcpu->kvm;
 	struct kvm_mmu_page_cache *pcache = &vcpu->arch.mmu_page_cache;
-	unsigned long vma_pagesize;
+	unsigned long vma_pagesize, mmu_seq;
 
 	down_read(&current->mm->mmap_sem);
 
@@ -623,6 +815,8 @@ int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned long hva,
 		return ret;
 	}
 
+	mmu_seq = kvm->mmu_notifier_seq;
+
 	hfn = gfn_to_pfn_prot(kvm, gfn, is_write, &writeable);
 	if (hfn == KVM_PFN_ERR_HWPOISON) {
 		if (is_vm_hugetlb_page(vma))
@@ -641,6 +835,9 @@ int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned long hva,
 
 	spin_lock(&kvm->mmu_lock);
 
+	if (mmu_notifier_retry(kvm, mmu_seq))
+		goto out_unlock;
+
 	if (writeable) {
 		kvm_set_pfn_dirty(hfn);
 		ret = stage2_map_page(kvm, pcache, gpa, hfn << PAGE_SHIFT,
@@ -653,6 +850,7 @@ int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, gpa_t gpa, unsigned long hva,
 	if (ret)
 		kvm_err("Failed to map in stage2\n");
 
+out_unlock:
 	spin_unlock(&kvm->mmu_lock);
 	kvm_set_pfn_accessed(hfn);
 	kvm_release_pfn_clean(hfn);
diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c
index c5aab5478c38..fd84b4d914dc 100644
--- a/arch/riscv/kvm/vm.c
+++ b/arch/riscv/kvm/vm.c
@@ -54,6 +54,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	switch (ext) {
 	case KVM_CAP_DEVICE_CTRL:
 	case KVM_CAP_USER_MEMORY:
+	case KVM_CAP_SYNC_MMU:
 	case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
 	case KVM_CAP_ONE_REG:
 	case KVM_CAP_READONLY_MEM:
-- 
2.17.1


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[PATCH v7 15/21] RISC-V: KVM: Add timer functionality

[Anup Patel]

From: Atish Patra <atish.patra@wdc.com>

The RISC-V hypervisor specification doesn't have any virtual timer
feature.

Due to this, the guest VCPU timer will be programmed via SBI calls.
The host will use a separate hrtimer event for each guest VCPU to
provide timer functionality. We inject a virtual timer interrupt to
the guest VCPU whenever the guest VCPU hrtimer event expires.

The following features are not supported yet and will be added in
future:
1. A time offset to adjust guest time from host time
2. A saved next event in guest vcpu for vm migration

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/riscv/include/asm/kvm_host.h       |   4 +
 arch/riscv/include/asm/kvm_vcpu_timer.h |  30 +++++++
 arch/riscv/kvm/Makefile                 |   2 +-
 arch/riscv/kvm/vcpu.c                   |   6 ++
 arch/riscv/kvm/vcpu_timer.c             | 113 ++++++++++++++++++++++++
 drivers/clocksource/timer-riscv.c       |   8 ++
 include/clocksource/timer-riscv.h       |  16 ++++
 7 files changed, 178 insertions(+), 1 deletion(-)
 create mode 100644 arch/riscv/include/asm/kvm_vcpu_timer.h
 create mode 100644 arch/riscv/kvm/vcpu_timer.c
 create mode 100644 include/clocksource/timer-riscv.h

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 79ceb2aa8ae6..9179ff019235 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -12,6 +12,7 @@
 #include <linux/types.h>
 #include <linux/kvm.h>
 #include <linux/kvm_types.h>
+#include <asm/kvm_vcpu_timer.h>
 
 #ifdef CONFIG_64BIT
 #define KVM_MAX_VCPUS			(1U << 16)
@@ -168,6 +169,9 @@ struct kvm_vcpu_arch {
 	unsigned long irqs_pending;
 	unsigned long irqs_pending_mask;
 
+	/* VCPU Timer */
+	struct kvm_vcpu_timer timer;
+
 	/* MMIO instruction details */
 	struct kvm_mmio_decode mmio_decode;
 
diff --git a/arch/riscv/include/asm/kvm_vcpu_timer.h b/arch/riscv/include/asm/kvm_vcpu_timer.h
new file mode 100644
index 000000000000..6f904d49e27e
--- /dev/null
+++ b/arch/riscv/include/asm/kvm_vcpu_timer.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *	Atish Patra <atish.patra@wdc.com>
+ */
+
+#ifndef __KVM_VCPU_RISCV_TIMER_H
+#define __KVM_VCPU_RISCV_TIMER_H
+
+#include <linux/hrtimer.h>
+
+struct kvm_vcpu_timer {
+	bool init_done;
+	/* Check if the timer is programmed */
+	bool next_set;
+	u64 next_cycles;
+	struct hrtimer hrt;
+	/* Mult & Shift values to get nanosec from cycles */
+	u32 mult;
+	u32 shift;
+};
+
+int kvm_riscv_vcpu_timer_init(struct kvm_vcpu *vcpu);
+int kvm_riscv_vcpu_timer_deinit(struct kvm_vcpu *vcpu);
+int kvm_riscv_vcpu_timer_reset(struct kvm_vcpu *vcpu);
+int kvm_riscv_vcpu_timer_next_event(struct kvm_vcpu *vcpu, u64 ncycles);
+
+#endif
diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
index c0f57f26c13d..3e0c7558320d 100644
--- a/arch/riscv/kvm/Makefile
+++ b/arch/riscv/kvm/Makefile
@@ -9,6 +9,6 @@ ccflags-y := -Ivirt/kvm -Iarch/riscv/kvm
 kvm-objs := $(common-objs-y)
 
 kvm-objs += main.o vm.o vmid.o tlb.o mmu.o
-kvm-objs += vcpu.o vcpu_exit.o vcpu_switch.o
+kvm-objs += vcpu.o vcpu_exit.o vcpu_switch.o vcpu_timer.o
 
 obj-$(CONFIG_KVM)	+= kvm.o
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 66158c0b90e6..7c270ba5e4b4 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -54,6 +54,8 @@ static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu)
 
 	memcpy(cntx, reset_cntx, sizeof(*cntx));
 
+	kvm_riscv_vcpu_timer_reset(vcpu);
+
 	WRITE_ONCE(vcpu->arch.irqs_pending, 0);
 	WRITE_ONCE(vcpu->arch.irqs_pending_mask, 0);
 }
@@ -108,6 +110,9 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 	cntx->hstatus |= HSTATUS_SP2P;
 	cntx->hstatus |= HSTATUS_SPV;
 
+	/* Setup VCPU timer */
+	kvm_riscv_vcpu_timer_init(vcpu);
+
 	/* Reset VCPU */
 	kvm_riscv_reset_vcpu(vcpu);
 
@@ -116,6 +121,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
 
 void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 {
+	kvm_riscv_vcpu_timer_deinit(vcpu);
 	kvm_riscv_stage2_flush_cache(vcpu);
 	kmem_cache_free(kvm_vcpu_cache, vcpu);
 }
diff --git a/arch/riscv/kvm/vcpu_timer.c b/arch/riscv/kvm/vcpu_timer.c
new file mode 100644
index 000000000000..9ffdd6ff8d6e
--- /dev/null
+++ b/arch/riscv/kvm/vcpu_timer.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Atish Patra <atish.patra@wdc.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/kvm_host.h>
+#include <clocksource/timer-riscv.h>
+#include <asm/csr.h>
+#include <asm/kvm_vcpu_timer.h>
+
+#define VCPU_TIMER_PROGRAM_THRESHOLD_NS		1000
+
+static enum hrtimer_restart kvm_riscv_vcpu_hrtimer_expired(struct hrtimer *h)
+{
+	struct kvm_vcpu_timer *t = container_of(h, struct kvm_vcpu_timer, hrt);
+	struct kvm_vcpu *vcpu = container_of(t, struct kvm_vcpu, arch.timer);
+
+	t->next_set = false;
+	kvm_riscv_vcpu_set_interrupt(vcpu, IRQ_S_TIMER);
+
+	return HRTIMER_NORESTART;
+}
+
+static u64 kvm_riscv_delta_cycles2ns(u64 cycles, struct kvm_vcpu_timer *t)
+{
+	unsigned long flags;
+	u64 cycles_now, cycles_delta, delta_ns;
+
+	local_irq_save(flags);
+	cycles_now = get_cycles64();
+	if (cycles_now < cycles)
+		cycles_delta = cycles - cycles_now;
+	else
+		cycles_delta = 0;
+	delta_ns = (cycles_delta * t->mult) >> t->shift;
+	local_irq_restore(flags);
+
+	return delta_ns;
+}
+
+static int kvm_riscv_vcpu_timer_cancel(struct kvm_vcpu_timer *t)
+{
+	if (!t->init_done || !t->next_set)
+		return -EINVAL;
+
+	hrtimer_cancel(&t->hrt);
+	t->next_set = false;
+
+	return 0;
+}
+
+int kvm_riscv_vcpu_timer_next_event(struct kvm_vcpu *vcpu, u64 ncycles)
+{
+	struct kvm_vcpu_timer *t = &vcpu->arch.timer;
+	u64 delta_ns = kvm_riscv_delta_cycles2ns(ncycles, t);
+
+	if (!t->init_done)
+		return -EINVAL;
+
+	if (t->next_set) {
+		hrtimer_cancel(&t->hrt);
+		t->next_set = false;
+	}
+
+	kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_S_TIMER);
+
+	if (delta_ns > VCPU_TIMER_PROGRAM_THRESHOLD_NS) {
+		hrtimer_start(&t->hrt, ktime_add_ns(ktime_get(), delta_ns),
+			      HRTIMER_MODE_ABS);
+		t->next_cycles = ncycles;
+		t->next_set = true;
+	} else
+		kvm_riscv_vcpu_set_interrupt(vcpu, IRQ_S_TIMER);
+
+	return 0;
+}
+
+int kvm_riscv_vcpu_timer_init(struct kvm_vcpu *vcpu)
+{
+	struct kvm_vcpu_timer *t = &vcpu->arch.timer;
+
+	if (t->init_done)
+		return -EINVAL;
+
+	hrtimer_init(&t->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+	t->hrt.function = kvm_riscv_vcpu_hrtimer_expired;
+	t->init_done = true;
+	t->next_set = false;
+
+	riscv_cs_get_mult_shift(&t->mult, &t->shift);
+
+	return 0;
+}
+
+int kvm_riscv_vcpu_timer_deinit(struct kvm_vcpu *vcpu)
+{
+	int ret;
+
+	ret = kvm_riscv_vcpu_timer_cancel(&vcpu->arch.timer);
+	vcpu->arch.timer.init_done = false;
+
+	return ret;
+}
+
+int kvm_riscv_vcpu_timer_reset(struct kvm_vcpu *vcpu)
+{
+	return kvm_riscv_vcpu_timer_cancel(&vcpu->arch.timer);
+}
diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
index 09e031176bc6..7c595203aa5c 100644
--- a/drivers/clocksource/timer-riscv.c
+++ b/drivers/clocksource/timer-riscv.c
@@ -8,6 +8,7 @@
 #include <linux/cpu.h>
 #include <linux/delay.h>
 #include <linux/irq.h>
+#include <linux/module.h>
 #include <linux/sched_clock.h>
 #include <asm/smp.h>
 #include <asm/sbi.h>
@@ -80,6 +81,13 @@ static int riscv_timer_dying_cpu(unsigned int cpu)
 	return 0;
 }
 
+void riscv_cs_get_mult_shift(u32 *mult, u32 *shift)
+{
+	*mult = riscv_clocksource.mult;
+	*shift = riscv_clocksource.shift;
+}
+EXPORT_SYMBOL_GPL(riscv_cs_get_mult_shift);
+
 /* called directly from the low-level interrupt handler */
 void riscv_timer_interrupt(void)
 {
diff --git a/include/clocksource/timer-riscv.h b/include/clocksource/timer-riscv.h
new file mode 100644
index 000000000000..e94e4feecbe8
--- /dev/null
+++ b/include/clocksource/timer-riscv.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *	Atish Patra <atish.patra@wdc.com>
+ */
+
+#ifndef __TIMER_RISCV_H
+#define __TIMER_RISCV_H
+
+#include <linux/types.h>
+
+void riscv_cs_get_mult_shift(u32 *mult, u32 *shift);
+
+#endif
-- 
2.17.1


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[PATCH v7 16/21] RISC-V: KVM: FP lazy save/restore

[Anup Patel]

From: Atish Patra <atish.patra@wdc.com>

This patch adds floating point (F and D extension) context save/restore
for guest VCPUs. The FP context is saved and restored lazily only when
kernel enter/exits the in-kernel run loop and not during the KVM world
switch. This way FP save/restore has minimal impact on KVM performance.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
 arch/riscv/include/asm/kvm_host.h |   5 +
 arch/riscv/kernel/asm-offsets.c   |  72 +++++++++++++
 arch/riscv/kvm/vcpu.c             |  81 ++++++++++++++
 arch/riscv/kvm/vcpu_switch.S      | 174 ++++++++++++++++++++++++++++++
 4 files changed, 332 insertions(+)

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 9179ff019235..928c67828b1b 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -117,6 +117,7 @@ struct kvm_cpu_context {
 	unsigned long sepc;
 	unsigned long sstatus;
 	unsigned long hstatus;
+	union __riscv_fp_state fp;
 };
 
 struct kvm_vcpu_csr {
@@ -236,6 +237,10 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 			unsigned long scause, unsigned long stval);
 
 void __kvm_riscv_switch_to(struct kvm_vcpu_arch *vcpu_arch);
+void __kvm_riscv_fp_f_save(struct kvm_cpu_context *context);
+void __kvm_riscv_fp_f_restore(struct kvm_cpu_context *context);
+void __kvm_riscv_fp_d_save(struct kvm_cpu_context *context);
+void __kvm_riscv_fp_d_restore(struct kvm_cpu_context *context);
 
 int kvm_riscv_vcpu_set_interrupt(struct kvm_vcpu *vcpu, unsigned int irq);
 int kvm_riscv_vcpu_unset_interrupt(struct kvm_vcpu *vcpu, unsigned int irq);
diff --git a/arch/riscv/kernel/asm-offsets.c b/arch/riscv/kernel/asm-offsets.c
index 711656710190..9980069a1acf 100644
--- a/arch/riscv/kernel/asm-offsets.c
+++ b/arch/riscv/kernel/asm-offsets.c
@@ -185,6 +185,78 @@ void asm_offsets(void)
 	OFFSET(KVM_ARCH_HOST_SSCRATCH, kvm_vcpu_arch, host_sscratch);
 	OFFSET(KVM_ARCH_HOST_STVEC, kvm_vcpu_arch, host_stvec);
 
+	/* F extension */
+
+	OFFSET(KVM_ARCH_FP_F_F0, kvm_cpu_context, fp.f.f[0]);
+	OFFSET(KVM_ARCH_FP_F_F1, kvm_cpu_context, fp.f.f[1]);
+	OFFSET(KVM_ARCH_FP_F_F2, kvm_cpu_context, fp.f.f[2]);
+	OFFSET(KVM_ARCH_FP_F_F3, kvm_cpu_context, fp.f.f[3]);
+	OFFSET(KVM_ARCH_FP_F_F4, kvm_cpu_context, fp.f.f[4]);
+	OFFSET(KVM_ARCH_FP_F_F5, kvm_cpu_context, fp.f.f[5]);
+	OFFSET(KVM_ARCH_FP_F_F6, kvm_cpu_context, fp.f.f[6]);
+	OFFSET(KVM_ARCH_FP_F_F7, kvm_cpu_context, fp.f.f[7]);
+	OFFSET(KVM_ARCH_FP_F_F8, kvm_cpu_context, fp.f.f[8]);
+	OFFSET(KVM_ARCH_FP_F_F9, kvm_cpu_context, fp.f.f[9]);
+	OFFSET(KVM_ARCH_FP_F_F10, kvm_cpu_context, fp.f.f[10]);
+	OFFSET(KVM_ARCH_FP_F_F11, kvm_cpu_context, fp.f.f[11]);
+	OFFSET(KVM_ARCH_FP_F_F12, kvm_cpu_context, fp.f.f[12]);
+	OFFSET(KVM_ARCH_FP_F_F13, kvm_cpu_context, fp.f.f[13]);
+	OFFSET(KVM_ARCH_FP_F_F14, kvm_cpu_context, fp.f.f[14]);
+	OFFSET(KVM_ARCH_FP_F_F15, kvm_cpu_context, fp.f.f[15]);
+	OFFSET(KVM_ARCH_FP_F_F16, kvm_cpu_context, fp.f.f[16]);
+	OFFSET(KVM_ARCH_FP_F_F17, kvm_cpu_context, fp.f.f[17]);
+	OFFSET(KVM_ARCH_FP_F_F18, kvm_cpu_context, fp.f.f[18]);
+	OFFSET(KVM_ARCH_FP_F_F19, kvm_cpu_context, fp.f.f[19]);
+	OFFSET(KVM_ARCH_FP_F_F20, kvm_cpu_context, fp.f.f[20]);
+	OFFSET(KVM_ARCH_FP_F_F21, kvm_cpu_context, fp.f.f[21]);
+	OFFSET(KVM_ARCH_FP_F_F22, kvm_cpu_context, fp.f.f[22]);
+	OFFSET(KVM_ARCH_FP_F_F23, kvm_cpu_context, fp.f.f[23]);
+	OFFSET(KVM_ARCH_FP_F_F24, kvm_cpu_context, fp.f.f[24]);
+	OFFSET(KVM_ARCH_FP_F_F25, kvm_cpu_context, fp.f.f[25]);
+	OFFSET(KVM_ARCH_FP_F_F26, kvm_cpu_context, fp.f.f[26]);
+	OFFSET(KVM_ARCH_FP_F_F27, kvm_cpu_context, fp.f.f[27]);
+	OFFSET(KVM_ARCH_FP_F_F28, kvm_cpu_context, fp.f.f[28]);
+	OFFSET(KVM_ARCH_FP_F_F29, kvm_cpu_context, fp.f.f[29]);
+	OFFSET(KVM_ARCH_FP_F_F30, kvm_cpu_context, fp.f.f[30]);
+	OFFSET(KVM_ARCH_FP_F_F31, kvm_cpu_context, fp.f.f[31]);
+	OFFSET(KVM_ARCH_FP_F_FCSR, kvm_cpu_context, fp.f.fcsr);
+
+	/* D extension */
+
+	OFFSET(KVM_ARCH_FP_D_F0, kvm_cpu_context, fp.d.f[0]);
+	OFFSET(KVM_ARCH_FP_D_F1, kvm_cpu_context, fp.d.f[1]);
+	OFFSET(KVM_ARCH_FP_D_F2, kvm_cpu_context, fp.d.f[2]);
+	OFFSET(KVM_ARCH_FP_D_F3, kvm_cpu_context, fp.d.f[3]);
+	OFFSET(KVM_ARCH_FP_D_F4, kvm_cpu_context, fp.d.f[4]);
+	OFFSET(KVM_ARCH_FP_D_F5, kvm_cpu_context, fp.d.f[5]);
+	OFFSET(KVM_ARCH_FP_D_F6, kvm_cpu_context, fp.d.f[6]);
+	OFFSET(KVM_ARCH_FP_D_F7, kvm_cpu_context, fp.d.f[7]);
+	OFFSET(KVM_ARCH_FP_D_F8, kvm_cpu_context, fp.d.f[8]);
+	OFFSET(KVM_ARCH_FP_D_F9, kvm_cpu_context, fp.d.f[9]);
+	OFFSET(KVM_ARCH_FP_D_F10, kvm_cpu_context, fp.d.f[10]);
+	OFFSET(KVM_ARCH_FP_D_F11, kvm_cpu_context, fp.d.f[11]);
+	OFFSET(KVM_ARCH_FP_D_F12, kvm_cpu_context, fp.d.f[12]);
+	OFFSET(KVM_ARCH_FP_D_F13, kvm_cpu_context, fp.d.f[13]);
+	OFFSET(KVM_ARCH_FP_D_F14, kvm_cpu_context, fp.d.f[14]);
+	OFFSET(KVM_ARCH_FP_D_F15, kvm_cpu_context, fp.d.f[15]);
+	OFFSET(KVM_ARCH_FP_D_F16, kvm_cpu_context, fp.d.f[16]);
+	OFFSET(KVM_ARCH_FP_D_F17, kvm_cpu_context, fp.d.f[17]);
+	OFFSET(KVM_ARCH_FP_D_F18, kvm_cpu_context, fp.d.f[18]);
+	OFFSET(KVM_ARCH_FP_D_F19, kvm_cpu_context, fp.d.f[19]);
+	OFFSET(KVM_ARCH_FP_D_F20, kvm_cpu_context, fp.d.f[20]);
+	OFFSET(KVM_ARCH_FP_D_F21, kvm_cpu_context, fp.d.f[21]);
+	OFFSET(KVM_ARCH_FP_D_F22, kvm_cpu_context, fp.d.f[22]);
+	OFFSET(KVM_ARCH_FP_D_F23, kvm_cpu_context, fp.d.f[23]);
+	OFFSET(KVM_ARCH_FP_D_F24, kvm_cpu_context, fp.d.f[24]);
+	OFFSET(KVM_ARCH_FP_D_F25, kvm_cpu_context, fp.d.f[25]);
+	OFFSET(KVM_ARCH_FP_D_F26, kvm_cpu_context, fp.d.f[26]);
+	OFFSET(KVM_ARCH_FP_D_F27, kvm_cpu_context, fp.d.f[27]);
+	OFFSET(KVM_ARCH_FP_D_F28, kvm_cpu_context, fp.d.f[28]);
+	OFFSET(KVM_ARCH_FP_D_F29, kvm_cpu_context, fp.d.f[29]);
+	OFFSET(KVM_ARCH_FP_D_F30, kvm_cpu_context, fp.d.f[30]);
+	OFFSET(KVM_ARCH_FP_D_F31, kvm_cpu_context, fp.d.f[31]);
+	OFFSET(KVM_ARCH_FP_D_FCSR, kvm_cpu_context, fp.d.fcsr);
+
 	/*
 	 * THREAD_{F,X}* might be larger than a S-type offset can handle, but
 	 * these are used in performance-sensitive assembly so we can't resort
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index 7c270ba5e4b4..bb3f2a857b22 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -32,6 +32,76 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
 	{ NULL }
 };
 
+#ifdef CONFIG_FPU
+static void kvm_riscv_vcpu_fp_reset(struct kvm_vcpu *vcpu)
+{
+	unsigned long isa = vcpu->arch.isa;
+	struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
+
+	cntx->sstatus &= ~SR_FS;
+	if (riscv_isa_extension_available(&isa, f) ||
+	    riscv_isa_extension_available(&isa, d))
+		cntx->sstatus |= SR_FS_INITIAL;
+	else
+		cntx->sstatus |= SR_FS_OFF;
+}
+
+static void kvm_riscv_vcpu_fp_clean(struct kvm_cpu_context *cntx)
+{
+	cntx->sstatus &= ~SR_FS;
+	cntx->sstatus |= SR_FS_CLEAN;
+}
+
+static void kvm_riscv_vcpu_guest_fp_save(struct kvm_cpu_context *cntx,
+					 unsigned long isa)
+{
+	if ((cntx->sstatus & SR_FS) == SR_FS_DIRTY) {
+		if (riscv_isa_extension_available(&isa, d))
+			__kvm_riscv_fp_d_save(cntx);
+		else if (riscv_isa_extension_available(&isa, f))
+			__kvm_riscv_fp_f_save(cntx);
+		kvm_riscv_vcpu_fp_clean(cntx);
+	}
+}
+
+static void kvm_riscv_vcpu_guest_fp_restore(struct kvm_cpu_context *cntx,
+					    unsigned long isa)
+{
+	if ((cntx->sstatus & SR_FS) != SR_FS_OFF) {
+		if (riscv_isa_extension_available(&isa, d))
+			__kvm_riscv_fp_d_restore(cntx);
+		else if (riscv_isa_extension_available(&isa, f))
+			__kvm_riscv_fp_f_restore(cntx);
+		kvm_riscv_vcpu_fp_clean(cntx);
+	}
+}
+
+static void kvm_riscv_vcpu_host_fp_save(struct kvm_cpu_context *cntx)
+{
+	/* No need to check host sstatus as it can be modified outside */
+	if (riscv_isa_extension_available(NULL, d))
+		__kvm_riscv_fp_d_save(cntx);
+	else if (riscv_isa_extension_available(NULL, f))
+		__kvm_riscv_fp_f_save(cntx);
+}
+
+static void kvm_riscv_vcpu_host_fp_restore(struct kvm_cpu_context *cntx)
+{
+	if (riscv_isa_extension_available(NULL, d))
+		__kvm_riscv_fp_d_restore(cntx);
+	else if (riscv_isa_extension_available(NULL, f))
+		__kvm_riscv_fp_f_restore(cntx);
+}
+#else
+static void kvm_riscv_vcpu_fp_reset(struct kvm_vcpu *vcpu) {}
+static void kvm_riscv_vcpu_guest_fp_save(struct kvm_cpu_context *cntx,
+					 unsigned long isa) {}
+static void kvm_riscv_vcpu_guest_fp_restore(struct kvm_cpu_context *cntx,
+					    unsigned long isa) {}
+static void kvm_riscv_vcpu_host_fp_save(struct kvm_cpu_context *cntx) {}
+static void kvm_riscv_vcpu_host_fp_restore(struct kvm_cpu_context *cntx) {}
+#endif
+
 #define KVM_RISCV_ISA_ALLOWED	(riscv_isa_extension_mask(a) | \
 				 riscv_isa_extension_mask(c) | \
 				 riscv_isa_extension_mask(d) | \
@@ -54,6 +124,8 @@ static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu)
 
 	memcpy(cntx, reset_cntx, sizeof(*cntx));
 
+	kvm_riscv_vcpu_fp_reset(vcpu);
+
 	kvm_riscv_vcpu_timer_reset(vcpu);
 
 	WRITE_ONCE(vcpu->arch.irqs_pending, 0);
@@ -223,6 +295,7 @@ static int kvm_riscv_vcpu_set_reg_config(struct kvm_vcpu *vcpu,
 			vcpu->arch.isa = reg_val;
 			vcpu->arch.isa &= riscv_isa_extension_base(NULL);
 			vcpu->arch.isa &= KVM_RISCV_ISA_ALLOWED;
+			kvm_riscv_vcpu_fp_reset(vcpu);
 		} else {
 			return -ENOTSUPP;
 		}
@@ -600,6 +673,10 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
 	kvm_riscv_stage2_update_hgatp(vcpu);
 
+	kvm_riscv_vcpu_host_fp_save(&vcpu->arch.host_context);
+	kvm_riscv_vcpu_guest_fp_restore(&vcpu->arch.guest_context,
+					vcpu->arch.isa);
+
 	vcpu->cpu = cpu;
 }
 
@@ -609,6 +686,10 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 
 	vcpu->cpu = -1;
 
+	kvm_riscv_vcpu_guest_fp_save(&vcpu->arch.guest_context,
+				     vcpu->arch.isa);
+	kvm_riscv_vcpu_host_fp_restore(&vcpu->arch.host_context);
+
 	csr_write(CSR_HGATP, 0);
 
 	csr->vsstatus = csr_read(CSR_VSSTATUS);
diff --git a/arch/riscv/kvm/vcpu_switch.S b/arch/riscv/kvm/vcpu_switch.S
index ee45c331666f..3b174c2c9dbc 100644
--- a/arch/riscv/kvm/vcpu_switch.S
+++ b/arch/riscv/kvm/vcpu_switch.S
@@ -200,3 +200,177 @@ ENTRY(__kvm_riscv_unpriv_trap)
 	csrr	a1, CSR_SCAUSE
 	sret
 ENDPROC(__kvm_riscv_unpriv_trap)
+
+#ifdef	CONFIG_FPU
+	.align 3
+	.global __kvm_riscv_fp_f_save
+__kvm_riscv_fp_f_save:
+	csrr t2, CSR_SSTATUS
+	li t1, SR_FS
+	csrs CSR_SSTATUS, t1
+	frcsr t0
+	fsw f0,  KVM_ARCH_FP_F_F0(a0)
+	fsw f1,  KVM_ARCH_FP_F_F1(a0)
+	fsw f2,  KVM_ARCH_FP_F_F2(a0)
+	fsw f3,  KVM_ARCH_FP_F_F3(a0)
+	fsw f4,  KVM_ARCH_FP_F_F4(a0)
+	fsw f5,  KVM_ARCH_FP_F_F5(a0)
+	fsw f6,  KVM_ARCH_FP_F_F6(a0)
+	fsw f7,  KVM_ARCH_FP_F_F7(a0)
+	fsw f8,  KVM_ARCH_FP_F_F8(a0)
+	fsw f9,  KVM_ARCH_FP_F_F9(a0)
+	fsw f10, KVM_ARCH_FP_F_F10(a0)
+	fsw f11, KVM_ARCH_FP_F_F11(a0)
+	fsw f12, KVM_ARCH_FP_F_F12(a0)
+	fsw f13, KVM_ARCH_FP_F_F13(a0)
+	fsw f14, KVM_ARCH_FP_F_F14(a0)
+	fsw f15, KVM_ARCH_FP_F_F15(a0)
+	fsw f16, KVM_ARCH_FP_F_F16(a0)
+	fsw f17, KVM_ARCH_FP_F_F17(a0)
+	fsw f18, KVM_ARCH_FP_F_F18(a0)
+	fsw f19, KVM_ARCH_FP_F_F19(a0)
+	fsw f20, KVM_ARCH_FP_F_F20(a0)
+	fsw f21, KVM_ARCH_FP_F_F21(a0)
+	fsw f22, KVM_ARCH_FP_F_F22(a0)
+	fsw f23, KVM_ARCH_FP_F_F23(a0)
+	fsw f24, KVM_ARCH_FP_F_F24(a0)
+	fsw f25, KVM_ARCH_FP_F_F25(a0)
+	fsw f26, KVM_ARCH_FP_F_F26(a0)
+	fsw f27, KVM_ARCH_FP_F_F27(a0)
+	fsw f28, KVM_ARCH_FP_F_F28(a0)
+	fsw f29, KVM_ARCH_FP_F_F29(a0)
+	fsw f30, KVM_ARCH_FP_F_F30(a0)
+	fsw f31, KVM_ARCH_FP_F_F31(a0)
+	sw t0, KVM_ARCH_FP_F_FCSR(a0)
+	csrw CSR_SSTATUS, t2
+	ret
+
+	.align 3
+	.global __kvm_riscv_fp_d_save
+__kvm_riscv_fp_d_save:
+	csrr t2, CSR_SSTATUS
+	li t1, SR_FS
+	csrs CSR_SSTATUS, t1
+	frcsr t0
+	fsd f0,  KVM_ARCH_FP_D_F0(a0)
+	fsd f1,  KVM_ARCH_FP_D_F1(a0)
+	fsd f2,  KVM_ARCH_FP_D_F2(a0)
+	fsd f3,  KVM_ARCH_FP_D_F3(a0)
+	fsd f4,  KVM_ARCH_FP_D_F4(a0)
+	fsd f5,  KVM_ARCH_FP_D_F5(a0)
+	fsd f6,  KVM_ARCH_FP_D_F6(a0)
+	fsd f7,  KVM_ARCH_FP_D_F7(a0)
+	fsd f8,  KVM_ARCH_FP_D_F8(a0)
+	fsd f9,  KVM_ARCH_FP_D_F9(a0)
+	fsd f10, KVM_ARCH_FP_D_F10(a0)
+	fsd f11, KVM_ARCH_FP_D_F11(a0)
+	fsd f12, KVM_ARCH_FP_D_F12(a0)
+	fsd f13, KVM_ARCH_FP_D_F13(a0)
+	fsd f14, KVM_ARCH_FP_D_F14(a0)
+	fsd f15, KVM_ARCH_FP_D_F15(a0)
+	fsd f16, KVM_ARCH_FP_D_F16(a0)
+	fsd f17, KVM_ARCH_FP_D_F17(a0)
+	fsd f18, KVM_ARCH_FP_D_F18(a0)
+	fsd f19, KVM_ARCH_FP_D_F19(a0)
+	fsd f20, KVM_ARCH_FP_D_F20(a0)
+	fsd f21, KVM_ARCH_FP_D_F21(a0)
+	fsd f22, KVM_ARCH_FP_D_F22(a0)
+	fsd f23, KVM_ARCH_FP_D_F23(a0)
+	fsd f24, KVM_ARCH_FP_D_F24(a0)
+	fsd f25, KVM_ARCH_FP_D_F25(a0)
+	fsd f26, KVM_ARCH_FP_D_F26(a0)
+	fsd f27, KVM_ARCH_FP_D_F27(a0)
+	fsd f28, KVM_ARCH_FP_D_F28(a0)
+	fsd f29, KVM_ARCH_FP_D_F29(a0)
+	fsd f30, KVM_ARCH_FP_D_F30(a0)
+	fsd f31, KVM_ARCH_FP_D_F31(a0)
+	sw t0, KVM_ARCH_FP_D_FCSR(a0)
+	csrw CSR_SSTATUS, t2
+	ret
+
+	.align 3
+	.global __kvm_riscv_fp_f_restore
+__kvm_riscv_fp_f_restore:
+	csrr t2, CSR_SSTATUS
+	li t1, SR_FS
+	lw t0, KVM_ARCH_FP_F_FCSR(a0)
+	csrs CSR_SSTATUS, t1
+	flw f0,  KVM_ARCH_FP_F_F0(a0)
+	flw f1,  KVM_ARCH_FP_F_F1(a0)
+	flw f2,  KVM_ARCH_FP_F_F2(a0)
+	flw f3,  KVM_ARCH_FP_F_F3(a0)
+	flw f4,  KVM_ARCH_FP_F_F4(a0)
+	flw f5,  KVM_ARCH_FP_F_F5(a0)
+	flw f6,  KVM_ARCH_FP_F_F6(a0)
+	flw f7,  KVM_ARCH_FP_F_F7(a0)
+	flw f8,  KVM_ARCH_FP_F_F8(a0)
+	flw f9,  KVM_ARCH_FP_F_F9(a0)
+	flw f10, KVM_ARCH_FP_F_F10(a0)
+	flw f11, KVM_ARCH_FP_F_F11(a0)
+	flw f12, KVM_ARCH_FP_F_F12(a0)
+	flw f13, KVM_ARCH_FP_F_F13(a0)
+	flw f14, KVM_ARCH_FP_F_F14(a0)
+	flw f15, KVM_ARCH_FP_F_F15(a0)
+	flw f16, KVM_ARCH_FP_F_F16(a0)
+	flw f17, KVM_ARCH_FP_F_F17(a0)
+	flw f18, KVM_ARCH_FP_F_F18(a0)
+	flw f19, KVM_ARCH_FP_F_F19(a0)
+	flw f20, KVM_ARCH_FP_F_F20(a0)
+	flw f21, KVM_ARCH_FP_F_F21(a0)
+	flw f22, KVM_ARCH_FP_F_F22(a0)
+	flw f23, KVM_ARCH_FP_F_F23(a0)
+	flw f24, KVM_ARCH_FP_F_F24(a0)
+	flw f25, KVM_ARCH_FP_F_F25(a0)
+	flw f26, KVM_ARCH_FP_F_F26(a0)
+	flw f27, KVM_ARCH_FP_F_F27(a0)
+	flw f28, KVM_ARCH_FP_F_F28(a0)
+	flw f29, KVM_ARCH_FP_F_F29(a0)
+	flw f30, KVM_ARCH_FP_F_F30(a0)
+	flw f31, KVM_ARCH_FP_F_F31(a0)
+	fscsr t0
+	csrw CSR_SSTATUS, t2
+	ret
+
+	.align 3
+	.global __kvm_riscv_fp_d_restore
+__kvm_riscv_fp_d_restore:
+	csrr t2, CSR_SSTATUS
+	li t1, SR_FS
+	lw t0, KVM_ARCH_FP_D_FCSR(a0)
+	csrs CSR_SSTATUS, t1
+	fld f0,  KVM_ARCH_FP_D_F0(a0)
+	fld f1,  KVM_ARCH_FP_D_F1(a0)
+	fld f2,  KVM_ARCH_FP_D_F2(a0)
+	fld f3,  KVM_ARCH_FP_D_F3(a0)
+	fld f4,  KVM_ARCH_FP_D_F4(a0)
+	fld f5,  KVM_ARCH_FP_D_F5(a0)
+	fld f6,  KVM_ARCH_FP_D_F6(a0)
+	fld f7,  KVM_ARCH_FP_D_F7(a0)
+	fld f8,  KVM_ARCH_FP_D_F8(a0)
+	fld f9,  KVM_ARCH_FP_D_F9(a0)
+	fld f10, KVM_ARCH_FP_D_F10(a0)
+	fld f11, KVM_ARCH_FP_D_F11(a0)
+	fld f12, KVM_ARCH_FP_D_F12(a0)
+	fld f13, KVM_ARCH_FP_D_F13(a0)
+	fld f14, KVM_ARCH_FP_D_F14(a0)
+	fld f15, KVM_ARCH_FP_D_F15(a0)
+	fld f16, KVM_ARCH_FP_D_F16(a0)
+	fld f17, KVM_ARCH_FP_D_F17(a0)
+	fld f18, KVM_ARCH_FP_D_F18(a0)
+	fld f19, KVM_ARCH_FP_D_F19(a0)
+	fld f20, KVM_ARCH_FP_D_F20(a0)
+	fld f21, KVM_ARCH_FP_D_F21(a0)
+	fld f22, KVM_ARCH_FP_D_F22(a0)
+	fld f23, KVM_ARCH_FP_D_F23(a0)
+	fld f24, KVM_ARCH_FP_D_F24(a0)
+	fld f25, KVM_ARCH_FP_D_F25(a0)
+	fld f26, KVM_ARCH_FP_D_F26(a0)
+	fld f27, KVM_ARCH_FP_D_F27(a0)
+	fld f28, KVM_ARCH_FP_D_F28(a0)
+	fld f29, KVM_ARCH_FP_D_F29(a0)
+	fld f30, KVM_ARCH_FP_D_F30(a0)
+	fld f31, KVM_ARCH_FP_D_F31(a0)
+	fscsr t0
+	csrw CSR_SSTATUS, t2
+	ret
+#endif
-- 
2.17.1


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[PATCH v7 17/21] RISC-V: KVM: Implement ONE REG interface for FP registers

[Anup Patel]

From: Atish Patra <atish.patra@wdc.com>

Add a KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctl interface for floating
point registers such as F0-F31 and FCSR. This support is added for
both 'F' and 'D' extensions.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
 arch/riscv/include/uapi/asm/kvm.h |  10 +++
 arch/riscv/kvm/vcpu.c             | 104 ++++++++++++++++++++++++++++++
 2 files changed, 114 insertions(+)

diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
index 08c4515ad71b..60184eaf720b 100644
--- a/arch/riscv/include/uapi/asm/kvm.h
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -89,6 +89,16 @@ struct kvm_riscv_config {
 #define KVM_REG_RISCV_CSR_REG(name)	\
 		(offsetof(struct kvm_sregs, name) / sizeof(unsigned long))
 
+/* F extension registers are mapped as type4 */
+#define KVM_REG_RISCV_FP_F		(0x04 << KVM_REG_RISCV_TYPE_SHIFT)
+#define KVM_REG_RISCV_FP_F_REG(name)	\
+		(offsetof(struct __riscv_f_ext_state, name) / sizeof(u32))
+
+/* D extension registers are mapped as type 5 */
+#define KVM_REG_RISCV_FP_D		(0x05 << KVM_REG_RISCV_TYPE_SHIFT)
+#define KVM_REG_RISCV_FP_D_REG(name)	\
+		(offsetof(struct __riscv_d_ext_state, name) / sizeof(u64))
+
 #endif
 
 #endif /* __LINUX_KVM_RISCV_H */
diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
index bb3f2a857b22..e52a608f8020 100644
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
@@ -427,6 +427,98 @@ static int kvm_riscv_vcpu_set_reg_csr(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
+static int kvm_riscv_vcpu_get_reg_fp(struct kvm_vcpu *vcpu,
+				     const struct kvm_one_reg *reg,
+				     unsigned long rtype)
+{
+	struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
+	unsigned long isa = vcpu->arch.isa;
+	unsigned long __user *uaddr =
+			(unsigned long __user *)(unsigned long)reg->addr;
+	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
+					    KVM_REG_SIZE_MASK |
+					    rtype);
+	void *reg_val;
+
+	if ((rtype == KVM_REG_RISCV_FP_F) &&
+	    riscv_isa_extension_available(&isa, f)) {
+		if (KVM_REG_SIZE(reg->id) != sizeof(u32))
+			return -EINVAL;
+		if (reg_num == KVM_REG_RISCV_FP_F_REG(fcsr))
+			reg_val = &cntx->fp.f.fcsr;
+		else if ((KVM_REG_RISCV_FP_F_REG(f[0]) <= reg_num) &&
+			  reg_num <= KVM_REG_RISCV_FP_F_REG(f[31]))
+			reg_val = &cntx->fp.f.f[reg_num];
+		else
+			return -EINVAL;
+	} else if ((rtype == KVM_REG_RISCV_FP_D) &&
+		   riscv_isa_extension_available(&isa, d)) {
+		if (reg_num == KVM_REG_RISCV_FP_D_REG(fcsr)) {
+			if (KVM_REG_SIZE(reg->id) != sizeof(u32))
+				return -EINVAL;
+			reg_val = &cntx->fp.d.fcsr;
+		} else if ((KVM_REG_RISCV_FP_D_REG(f[0]) <= reg_num) &&
+			   reg_num <= KVM_REG_RISCV_FP_D_REG(f[31])) {
+			if (KVM_REG_SIZE(reg->id) != sizeof(u64))
+				return -EINVAL;
+			reg_val = &cntx->fp.d.f[reg_num];
+		} else
+			return -EINVAL;
+	} else
+		return -EINVAL;
+
+	if (copy_to_user(uaddr, reg_val, KVM_REG_SIZE(reg->id)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int kvm_riscv_vcpu_set_reg_fp(struct kvm_vcpu *vcpu,
+				     const struct kvm_one_reg *reg,
+				     unsigned long rtype)
+{
+	struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
+	unsigned long isa = vcpu->arch.isa;
+	unsigned long __user *uaddr =
+			(unsigned long __user *)(unsigned long)reg->addr;
+	unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK |
+					    KVM_REG_SIZE_MASK |
+					    rtype);
+	void *reg_val;
+
+	if ((rtype == KVM_REG_RISCV_FP_F) &&
+	    riscv_isa_extension_available(&isa, f)) {
+		if (KVM_REG_SIZE(reg->id) != sizeof(u32))
+			return -EINVAL;
+		if (reg_num == KVM_REG_RISCV_FP_F_REG(fcsr))
+			reg_val = &cntx->fp.f.fcsr;
+		else if ((KVM_REG_RISCV_FP_F_REG(f[0]) <= reg_num) &&
+			  reg_num <= KVM_REG_RISCV_FP_F_REG(f[31]))
+			reg_val = &cntx->fp.f.f[reg_num];
+		else
+			return -EINVAL;
+	} else if ((rtype == KVM_REG_RISCV_FP_D) &&
+		   riscv_isa_extension_available(&isa, d)) {
+		if (reg_num == KVM_REG_RISCV_FP_D_REG(fcsr)) {
+			if (KVM_REG_SIZE(reg->id) != sizeof(u32))
+				return -EINVAL;
+			reg_val = &cntx->fp.d.fcsr;
+		} else if ((KVM_REG_RISCV_FP_D_REG(f[0]) <= reg_num) &&
+			   reg_num <= KVM_REG_RISCV_FP_D_REG(f[31])) {
+			if (KVM_REG_SIZE(reg->id) != sizeof(u64))
+				return -EINVAL;
+			reg_val = &cntx->fp.d.f[reg_num];
+		} else
+			return -EINVAL;
+	} else
+		return -EINVAL;
+
+	if (copy_from_user(reg_val, uaddr, KVM_REG_SIZE(reg->id)))
+		return -EFAULT;
+
+	return 0;
+}
+
 static int kvm_riscv_vcpu_set_reg(struct kvm_vcpu *vcpu,
 				  const struct kvm_one_reg *reg)
 {
@@ -436,6 +528,12 @@ static int kvm_riscv_vcpu_set_reg(struct kvm_vcpu *vcpu,
 		return kvm_riscv_vcpu_set_reg_core(vcpu, reg);
 	else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CSR)
 		return kvm_riscv_vcpu_set_reg_csr(vcpu, reg);
+	else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_FP_F)
+		return kvm_riscv_vcpu_set_reg_fp(vcpu, reg,
+						 KVM_REG_RISCV_FP_F);
+	else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_FP_D)
+		return kvm_riscv_vcpu_set_reg_fp(vcpu, reg,
+						 KVM_REG_RISCV_FP_D);
 
 	return -EINVAL;
 }
@@ -449,6 +547,12 @@ static int kvm_riscv_vcpu_get_reg(struct kvm_vcpu *vcpu,
 		return kvm_riscv_vcpu_get_reg_core(vcpu, reg);
 	else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CSR)
 		return kvm_riscv_vcpu_get_reg_csr(vcpu, reg);
+	else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_FP_F)
+		return kvm_riscv_vcpu_get_reg_fp(vcpu, reg,
+						 KVM_REG_RISCV_FP_F);
+	else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_FP_D)
+		return kvm_riscv_vcpu_get_reg_fp(vcpu, reg,
+						 KVM_REG_RISCV_FP_D);
 
 	return -EINVAL;
 }
-- 
2.17.1


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[PATCH v7 18/21] RISC-V: KVM: Add SBI v0.1 support

[Anup Patel]

From: Atish Patra <atish.patra@wdc.com>

The KVM host kernel running in HS-mode needs to handle SBI calls coming
from guest kernel running in VS-mode.

This patch adds SBI v0.1 support in KVM RISC-V. All the SBI calls are
implemented correctly except remote tlb flushes. For remote TLB flushes,
we are doing full TLB flush and this will be optimized in future.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/riscv/include/asm/kvm_host.h |   2 +
 arch/riscv/kvm/Makefile           |   2 +-
 arch/riscv/kvm/vcpu_exit.c        |   3 +
 arch/riscv/kvm/vcpu_sbi.c         | 104 ++++++++++++++++++++++++++++++
 4 files changed, 110 insertions(+), 1 deletion(-)
 create mode 100644 arch/riscv/kvm/vcpu_sbi.c

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
index 928c67828b1b..269bfa5641b1 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -250,4 +250,6 @@ bool kvm_riscv_vcpu_has_interrupt(struct kvm_vcpu *vcpu);
 void kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu);
 void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu);
 
+int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu);
+
 #endif /* __RISCV_KVM_HOST_H__ */
diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
index 3e0c7558320d..b56dc1650d2c 100644
--- a/arch/riscv/kvm/Makefile
+++ b/arch/riscv/kvm/Makefile
@@ -9,6 +9,6 @@ ccflags-y := -Ivirt/kvm -Iarch/riscv/kvm
 kvm-objs := $(common-objs-y)
 
 kvm-objs += main.o vm.o vmid.o tlb.o mmu.o
-kvm-objs += vcpu.o vcpu_exit.o vcpu_switch.o vcpu_timer.o
+kvm-objs += vcpu.o vcpu_exit.o vcpu_switch.o vcpu_timer.o vcpu_sbi.o
 
 obj-$(CONFIG_KVM)	+= kvm.o
diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
index 39469f67b241..0ee4e8943f4f 100644
--- a/arch/riscv/kvm/vcpu_exit.c
+++ b/arch/riscv/kvm/vcpu_exit.c
@@ -594,6 +594,9 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
 		    (vcpu->arch.guest_context.hstatus & HSTATUS_STL))
 			ret = stage2_page_fault(vcpu, run, scause, stval);
 		break;
+	case EXC_SUPERVISOR_SYSCALL:
+		if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV)
+			ret = kvm_riscv_vcpu_sbi_ecall(vcpu);
 	default:
 		break;
 	};
diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
new file mode 100644
index 000000000000..b415b8b54bb1
--- /dev/null
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0
+/**
+ * Copyright (c) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Atish Patra <atish.patra@wdc.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/kvm_host.h>
+#include <asm/csr.h>
+#include <asm/kvm_vcpu_timer.h>
+
+#define SBI_VERSION_MAJOR			0
+#define SBI_VERSION_MINOR			1
+
+static void kvm_sbi_system_shutdown(struct kvm_vcpu *vcpu, u32 type)
+{
+	int i;
+	struct kvm_vcpu *tmp;
+
+	kvm_for_each_vcpu(i, tmp, vcpu->kvm)
+		tmp->arch.power_off = true;
+	kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
+
+	memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
+	vcpu->run->system_event.type = type;
+	vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
+}
+
+int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu)
+{
+	int i, ret = 1;
+	u64 next_cycle;
+	struct kvm_vcpu *rvcpu;
+	bool next_sepc = true;
+	ulong hmask, ut_scause = 0;
+	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
+
+	if (!cp)
+		return -EINVAL;
+
+	switch (cp->a7) {
+	case SBI_SET_TIMER:
+#if __riscv_xlen == 32
+		next_cycle = ((u64)cp->a1 << 32) | (u64)cp->a0;
+#else
+		next_cycle = (u64)cp->a0;
+#endif
+		kvm_riscv_vcpu_timer_next_event(vcpu, next_cycle);
+		break;
+	case SBI_CLEAR_IPI:
+		kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_S_SOFT);
+		break;
+	case SBI_SEND_IPI:
+		hmask = kvm_riscv_vcpu_unpriv_read(vcpu, false, cp->a0,
+						   &ut_scause);
+		if (ut_scause) {
+			kvm_riscv_vcpu_trap_redirect(vcpu, ut_scause,
+						     cp->a0);
+			next_sepc = false;
+		} else {
+			for_each_set_bit(i, &hmask, BITS_PER_LONG) {
+				rvcpu = kvm_get_vcpu_by_id(vcpu->kvm, i);
+				kvm_riscv_vcpu_set_interrupt(rvcpu, IRQ_S_SOFT);
+			}
+		}
+		break;
+	case SBI_SHUTDOWN:
+		kvm_sbi_system_shutdown(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
+		ret = 0;
+		break;
+	case SBI_REMOTE_FENCE_I:
+		sbi_remote_fence_i(NULL);
+		break;
+	/*
+	 * TODO: There should be a way to call remote hfence.bvma.
+	 * Preferred method is now a SBI call. Until then, just flush
+	 * all tlbs.
+	 */
+	case SBI_REMOTE_SFENCE_VMA:
+		/* TODO: Parse vma range. */
+		sbi_remote_sfence_vma(NULL, 0, 0);
+		break;
+	case SBI_REMOTE_SFENCE_VMA_ASID:
+		/* TODO: Parse vma range for given ASID */
+		sbi_remote_sfence_vma(NULL, 0, 0);
+		break;
+	default:
+		/*
+		 * For now, just return error to Guest.
+		 * TODO: In-future, we will route unsupported SBI calls
+		 * to user-space.
+		 */
+		cp->a0 = -ENOTSUPP;
+		break;
+	};
+
+	if (ret >= 0)
+		cp->sepc += 4;
+
+	return ret;
+}
-- 
2.17.1


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Re: [PATCH v7 18/21] RISC-V: KVM: Add SBI v0.1 support

[Andreas Schwab]

On Sep 04 2019, Anup Patel <Anup.Patel@wdc.com> wrote:

> From: Atish Patra <atish.patra@wdc.com>
>
> The KVM host kernel running in HS-mode needs to handle SBI calls coming
> from guest kernel running in VS-mode.
>
> This patch adds SBI v0.1 support in KVM RISC-V. All the SBI calls are
> implemented correctly except remote tlb flushes. For remote TLB flushes,
> we are doing full TLB flush and this will be optimized in future.

Note that this conflicts with
https://patchwork.kernel.org/patch/11107221/ which removes <asm/sbi.h>
from <asm/tlbflush.h>.  You should probably include that header
explicitly in arch/riscv/kvm/vcpu_sbi.c.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

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Re: [PATCH v7 18/21] RISC-V: KVM: Add SBI v0.1 support

[Alexander Graf]

On 04.09.19 18:16, Anup Patel wrote:
> From: Atish Patra <atish.patra@wdc.com>
> 
> The KVM host kernel running in HS-mode needs to handle SBI calls coming
> from guest kernel running in VS-mode.
> 
> This patch adds SBI v0.1 support in KVM RISC-V. All the SBI calls are
> implemented correctly except remote tlb flushes. For remote TLB flushes,
> we are doing full TLB flush and this will be optimized in future.
> 
> Signed-off-by: Atish Patra <atish.patra@wdc.com>
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   arch/riscv/include/asm/kvm_host.h |   2 +
>   arch/riscv/kvm/Makefile           |   2 +-
>   arch/riscv/kvm/vcpu_exit.c        |   3 +
>   arch/riscv/kvm/vcpu_sbi.c         | 104 ++++++++++++++++++++++++++++++
>   4 files changed, 110 insertions(+), 1 deletion(-)
>   create mode 100644 arch/riscv/kvm/vcpu_sbi.c
> 
> diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
> index 928c67828b1b..269bfa5641b1 100644
> --- a/arch/riscv/include/asm/kvm_host.h
> +++ b/arch/riscv/include/asm/kvm_host.h
> @@ -250,4 +250,6 @@ bool kvm_riscv_vcpu_has_interrupt(struct kvm_vcpu *vcpu);
>   void kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu);
>   void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu);
>   
> +int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu);
> +
>   #endif /* __RISCV_KVM_HOST_H__ */
> diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
> index 3e0c7558320d..b56dc1650d2c 100644
> --- a/arch/riscv/kvm/Makefile
> +++ b/arch/riscv/kvm/Makefile
> @@ -9,6 +9,6 @@ ccflags-y := -Ivirt/kvm -Iarch/riscv/kvm
>   kvm-objs := $(common-objs-y)
>   
>   kvm-objs += main.o vm.o vmid.o tlb.o mmu.o
> -kvm-objs += vcpu.o vcpu_exit.o vcpu_switch.o vcpu_timer.o
> +kvm-objs += vcpu.o vcpu_exit.o vcpu_switch.o vcpu_timer.o vcpu_sbi.o
>   
>   obj-$(CONFIG_KVM)	+= kvm.o
> diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
> index 39469f67b241..0ee4e8943f4f 100644
> --- a/arch/riscv/kvm/vcpu_exit.c
> +++ b/arch/riscv/kvm/vcpu_exit.c
> @@ -594,6 +594,9 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
>   		    (vcpu->arch.guest_context.hstatus & HSTATUS_STL))
>   			ret = stage2_page_fault(vcpu, run, scause, stval);
>   		break;
> +	case EXC_SUPERVISOR_SYSCALL:
> +		if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV)
> +			ret = kvm_riscv_vcpu_sbi_ecall(vcpu);

implicit fall-through

>   	default:
>   		break;
>   	};
> diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
> new file mode 100644
> index 000000000000..b415b8b54bb1
> --- /dev/null
> +++ b/arch/riscv/kvm/vcpu_sbi.c
> @@ -0,0 +1,104 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/**
> + * Copyright (c) 2019 Western Digital Corporation or its affiliates.
> + *
> + * Authors:
> + *     Atish Patra <atish.patra@wdc.com>
> + */
> +
> +#include <linux/errno.h>
> +#include <linux/err.h>
> +#include <linux/kvm_host.h>
> +#include <asm/csr.h>
> +#include <asm/kvm_vcpu_timer.h>
> +
> +#define SBI_VERSION_MAJOR			0
> +#define SBI_VERSION_MINOR			1
> +
> +static void kvm_sbi_system_shutdown(struct kvm_vcpu *vcpu, u32 type)
> +{
> +	int i;
> +	struct kvm_vcpu *tmp;
> +
> +	kvm_for_each_vcpu(i, tmp, vcpu->kvm)
> +		tmp->arch.power_off = true;
> +	kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
> +
> +	memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
> +	vcpu->run->system_event.type = type;
> +	vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;

Is there a particular reason this has to be implemented in kernel space? 
It's not performance critical and all stopping vcpus is something user 
space should be able to do as well, no?

> +}
> +
> +int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu)
> +{
> +	int i, ret = 1;
> +	u64 next_cycle;
> +	struct kvm_vcpu *rvcpu;
> +	bool next_sepc = true;
> +	ulong hmask, ut_scause = 0;
> +	struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
> +
> +	if (!cp)
> +		return -EINVAL;
> +
> +	switch (cp->a7) {
> +	case SBI_SET_TIMER:
> +#if __riscv_xlen == 32
> +		next_cycle = ((u64)cp->a1 << 32) | (u64)cp->a0;
> +#else
> +		next_cycle = (u64)cp->a0;
> +#endif
> +		kvm_riscv_vcpu_timer_next_event(vcpu, next_cycle);
> +		break;
> +	case SBI_CLEAR_IPI:
> +		kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_S_SOFT);
> +		break;
> +	case SBI_SEND_IPI:
> +		hmask = kvm_riscv_vcpu_unpriv_read(vcpu, false, cp->a0,
> +						   &ut_scause);
> +		if (ut_scause) {
> +			kvm_riscv_vcpu_trap_redirect(vcpu, ut_scause,
> +						     cp->a0);
> +			next_sepc = false;
> +		} else {
> +			for_each_set_bit(i, &hmask, BITS_PER_LONG) {
> +				rvcpu = kvm_get_vcpu_by_id(vcpu->kvm, i);
> +				kvm_riscv_vcpu_set_interrupt(rvcpu, IRQ_S_SOFT);
> +			}
> +		}
> +		break;
> +	case SBI_SHUTDOWN:
> +		kvm_sbi_system_shutdown(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
> +		ret = 0;
> +		break;
> +	case SBI_REMOTE_FENCE_I:
> +		sbi_remote_fence_i(NULL);
> +		break;
> +	/*
> +	 * TODO: There should be a way to call remote hfence.bvma.
> +	 * Preferred method is now a SBI call. Until then, just flush
> +	 * all tlbs.
> +	 */
> +	case SBI_REMOTE_SFENCE_VMA:
> +		/* TODO: Parse vma range. */
> +		sbi_remote_sfence_vma(NULL, 0, 0);
> +		break;
> +	case SBI_REMOTE_SFENCE_VMA_ASID:
> +		/* TODO: Parse vma range for given ASID */
> +		sbi_remote_sfence_vma(NULL, 0, 0);
> +		break;
> +	default:
> +		/*
> +		 * For now, just return error to Guest.
> +		 * TODO: In-future, we will route unsupported SBI calls
> +		 * to user-space.
> +		 */
> +		cp->a0 = -ENOTSUPP;
> +		break;
> +	};
> +
> +	if (ret >= 0)
> +		cp->sepc += 4;

I don't see you ever setting ret except for shutdown?

Really, now is the time to plumb SBI calls down to user space. It allows 
you to have a clean shutdown story from day 1.


Alex



Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Ralf Herbrich
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879


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Re: [PATCH v7 18/21] RISC-V: KVM: Add SBI v0.1 support

[Anup Patel]

On Mon, Sep 23, 2019 at 12:31 PM Alexander Graf <graf@amazon.com> wrote:
>
>
>
> On 04.09.19 18:16, Anup Patel wrote:
> > From: Atish Patra <atish.patra@wdc.com>
> >
> > The KVM host kernel running in HS-mode needs to handle SBI calls coming
> > from guest kernel running in VS-mode.
> >
> > This patch adds SBI v0.1 support in KVM RISC-V. All the SBI calls are
> > implemented correctly except remote tlb flushes. For remote TLB flushes,
> > we are doing full TLB flush and this will be optimized in future.
> >
> > Signed-off-by: Atish Patra <atish.patra@wdc.com>
> > Signed-off-by: Anup Patel <anup.patel@wdc.com>
> > Acked-by: Paolo Bonzini <pbonzini@redhat.com>
> > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> > ---
> >   arch/riscv/include/asm/kvm_host.h |   2 +
> >   arch/riscv/kvm/Makefile           |   2 +-
> >   arch/riscv/kvm/vcpu_exit.c        |   3 +
> >   arch/riscv/kvm/vcpu_sbi.c         | 104 ++++++++++++++++++++++++++++++
> >   4 files changed, 110 insertions(+), 1 deletion(-)
> >   create mode 100644 arch/riscv/kvm/vcpu_sbi.c
> >
> > diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
> > index 928c67828b1b..269bfa5641b1 100644
> > --- a/arch/riscv/include/asm/kvm_host.h
> > +++ b/arch/riscv/include/asm/kvm_host.h
> > @@ -250,4 +250,6 @@ bool kvm_riscv_vcpu_has_interrupt(struct kvm_vcpu *vcpu);
> >   void kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu);
> >   void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu);
> >
> > +int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu);
> > +
> >   #endif /* __RISCV_KVM_HOST_H__ */
> > diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
> > index 3e0c7558320d..b56dc1650d2c 100644
> > --- a/arch/riscv/kvm/Makefile
> > +++ b/arch/riscv/kvm/Makefile
> > @@ -9,6 +9,6 @@ ccflags-y := -Ivirt/kvm -Iarch/riscv/kvm
> >   kvm-objs := $(common-objs-y)
> >
> >   kvm-objs += main.o vm.o vmid.o tlb.o mmu.o
> > -kvm-objs += vcpu.o vcpu_exit.o vcpu_switch.o vcpu_timer.o
> > +kvm-objs += vcpu.o vcpu_exit.o vcpu_switch.o vcpu_timer.o vcpu_sbi.o
> >
> >   obj-$(CONFIG_KVM)   += kvm.o
> > diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
> > index 39469f67b241..0ee4e8943f4f 100644
> > --- a/arch/riscv/kvm/vcpu_exit.c
> > +++ b/arch/riscv/kvm/vcpu_exit.c
> > @@ -594,6 +594,9 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
> >                   (vcpu->arch.guest_context.hstatus & HSTATUS_STL))
> >                       ret = stage2_page_fault(vcpu, run, scause, stval);
> >               break;
> > +     case EXC_SUPERVISOR_SYSCALL:
> > +             if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV)
> > +                     ret = kvm_riscv_vcpu_sbi_ecall(vcpu);
>
> implicit fall-through

Okay, I will add break here.

>
> >       default:
> >               break;
> >       };
> > diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
> > new file mode 100644
> > index 000000000000..b415b8b54bb1
> > --- /dev/null
> > +++ b/arch/riscv/kvm/vcpu_sbi.c
> > @@ -0,0 +1,104 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/**
> > + * Copyright (c) 2019 Western Digital Corporation or its affiliates.
> > + *
> > + * Authors:
> > + *     Atish Patra <atish.patra@wdc.com>
> > + */
> > +
> > +#include <linux/errno.h>
> > +#include <linux/err.h>
> > +#include <linux/kvm_host.h>
> > +#include <asm/csr.h>
> > +#include <asm/kvm_vcpu_timer.h>
> > +
> > +#define SBI_VERSION_MAJOR                    0
> > +#define SBI_VERSION_MINOR                    1
> > +
> > +static void kvm_sbi_system_shutdown(struct kvm_vcpu *vcpu, u32 type)
> > +{
> > +     int i;
> > +     struct kvm_vcpu *tmp;
> > +
> > +     kvm_for_each_vcpu(i, tmp, vcpu->kvm)
> > +             tmp->arch.power_off = true;
> > +     kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
> > +
> > +     memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
> > +     vcpu->run->system_event.type = type;
> > +     vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT;
>
> Is there a particular reason this has to be implemented in kernel space?

It's not implemented in kernel space. We are forwarding it to user space
using exit reason KVM_EXIT_SYSTEM_EVENT. These exit reason is
arch independent and both QEMU and KVMTOOL already implement
it in arch independent way.

> It's not performance critical and all stopping vcpus is something user
> space should be able to do as well, no?

Yes, it's not performance critical but it's done in user space.

>
> > +}
> > +
> > +int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu)
> > +{
> > +     int i, ret = 1;
> > +     u64 next_cycle;
> > +     struct kvm_vcpu *rvcpu;
> > +     bool next_sepc = true;
> > +     ulong hmask, ut_scause = 0;
> > +     struct kvm_cpu_context *cp = &vcpu->arch.guest_context;
> > +
> > +     if (!cp)
> > +             return -EINVAL;
> > +
> > +     switch (cp->a7) {
> > +     case SBI_SET_TIMER:
> > +#if __riscv_xlen == 32
> > +             next_cycle = ((u64)cp->a1 << 32) | (u64)cp->a0;
> > +#else
> > +             next_cycle = (u64)cp->a0;
> > +#endif
> > +             kvm_riscv_vcpu_timer_next_event(vcpu, next_cycle);
> > +             break;
> > +     case SBI_CLEAR_IPI:
> > +             kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_S_SOFT);
> > +             break;
> > +     case SBI_SEND_IPI:
> > +             hmask = kvm_riscv_vcpu_unpriv_read(vcpu, false, cp->a0,
> > +                                                &ut_scause);
> > +             if (ut_scause) {
> > +                     kvm_riscv_vcpu_trap_redirect(vcpu, ut_scause,
> > +                                                  cp->a0);
> > +                     next_sepc = false;
> > +             } else {
> > +                     for_each_set_bit(i, &hmask, BITS_PER_LONG) {
> > +                             rvcpu = kvm_get_vcpu_by_id(vcpu->kvm, i);
> > +                             kvm_riscv_vcpu_set_interrupt(rvcpu, IRQ_S_SOFT);
> > +                     }
> > +             }
> > +             break;
> > +     case SBI_SHUTDOWN:
> > +             kvm_sbi_system_shutdown(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
> > +             ret = 0;
> > +             break;
> > +     case SBI_REMOTE_FENCE_I:
> > +             sbi_remote_fence_i(NULL);
> > +             break;
> > +     /*
> > +      * TODO: There should be a way to call remote hfence.bvma.
> > +      * Preferred method is now a SBI call. Until then, just flush
> > +      * all tlbs.
> > +      */
> > +     case SBI_REMOTE_SFENCE_VMA:
> > +             /* TODO: Parse vma range. */
> > +             sbi_remote_sfence_vma(NULL, 0, 0);
> > +             break;
> > +     case SBI_REMOTE_SFENCE_VMA_ASID:
> > +             /* TODO: Parse vma range for given ASID */
> > +             sbi_remote_sfence_vma(NULL, 0, 0);
> > +             break;
> > +     default:
> > +             /*
> > +              * For now, just return error to Guest.
> > +              * TODO: In-future, we will route unsupported SBI calls
> > +              * to user-space.
> > +              */
> > +             cp->a0 = -ENOTSUPP;
> > +             break;
> > +     };
> > +
> > +     if (ret >= 0)
> > +             cp->sepc += 4;
>
> I don't see you ever setting ret except for shutdown?
>
> Really, now is the time to plumb SBI calls down to user space. It allows
> you to have a clean shutdown story from day 1.

I agree with you.

I will implement unsupported SBI call forwarding to user-space in v8 series.

Regards,
Anup

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[PATCH v7 19/21] RISC-V: KVM: Document RISC-V specific parts of KVM API.

[Anup Patel]

Document RISC-V specific parts of the KVM API, such as:
 - The interrupt numbers passed to the KVM_INTERRUPT ioctl.
 - The states supported by the KVM_{GET,SET}_MP_STATE ioctls.
 - The registers supported by the KVM_{GET,SET}_ONE_REG interface
   and the encoding of those register ids.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
---
 Documentation/virt/kvm/api.txt | 141 +++++++++++++++++++++++++++++++--
 1 file changed, 134 insertions(+), 7 deletions(-)

diff --git a/Documentation/virt/kvm/api.txt b/Documentation/virt/kvm/api.txt
index 2d067767b617..065c664b0d48 100644
--- a/Documentation/virt/kvm/api.txt
+++ b/Documentation/virt/kvm/api.txt
@@ -471,7 +471,7 @@ struct kvm_translation {
 4.16 KVM_INTERRUPT
 
 Capability: basic
-Architectures: x86, ppc, mips
+Architectures: x86, ppc, mips, riscv
 Type: vcpu ioctl
 Parameters: struct kvm_interrupt (in)
 Returns: 0 on success, negative on failure.
@@ -531,6 +531,22 @@ interrupt number dequeues the interrupt.
 
 This is an asynchronous vcpu ioctl and can be invoked from any thread.
 
+RISC-V:
+
+Queues an external interrupt to be injected into the virutal CPU. This ioctl
+is overloaded with 2 different irq values:
+
+a) KVM_INTERRUPT_SET
+
+  This sets external interrupt for a virtual CPU and it will receive
+  once it is ready.
+
+b) KVM_INTERRUPT_UNSET
+
+  This clears pending external interrupt for a virtual CPU.
+
+This is an asynchronous vcpu ioctl and can be invoked from any thread.
+
 
 4.17 KVM_DEBUG_GUEST
 
@@ -1206,7 +1222,7 @@ for vm-wide capabilities.
 4.38 KVM_GET_MP_STATE
 
 Capability: KVM_CAP_MP_STATE
-Architectures: x86, s390, arm, arm64
+Architectures: x86, s390, arm, arm64, riscv
 Type: vcpu ioctl
 Parameters: struct kvm_mp_state (out)
 Returns: 0 on success; -1 on error
@@ -1220,7 +1236,8 @@ uniprocessor guests).
 
 Possible values are:
 
- - KVM_MP_STATE_RUNNABLE:        the vcpu is currently running [x86,arm/arm64]
+ - KVM_MP_STATE_RUNNABLE:        the vcpu is currently running
+                                 [x86,arm/arm64,riscv]
  - KVM_MP_STATE_UNINITIALIZED:   the vcpu is an application processor (AP)
                                  which has not yet received an INIT signal [x86]
  - KVM_MP_STATE_INIT_RECEIVED:   the vcpu has received an INIT signal, and is
@@ -1229,7 +1246,7 @@ Possible values are:
                                  is waiting for an interrupt [x86]
  - KVM_MP_STATE_SIPI_RECEIVED:   the vcpu has just received a SIPI (vector
                                  accessible via KVM_GET_VCPU_EVENTS) [x86]
- - KVM_MP_STATE_STOPPED:         the vcpu is stopped [s390,arm/arm64]
+ - KVM_MP_STATE_STOPPED:         the vcpu is stopped [s390,arm/arm64,riscv]
  - KVM_MP_STATE_CHECK_STOP:      the vcpu is in a special error state [s390]
  - KVM_MP_STATE_OPERATING:       the vcpu is operating (running or halted)
                                  [s390]
@@ -1240,7 +1257,7 @@ On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an
 in-kernel irqchip, the multiprocessing state must be maintained by userspace on
 these architectures.
 
-For arm/arm64:
+For arm/arm64/riscv:
 
 The only states that are valid are KVM_MP_STATE_STOPPED and
 KVM_MP_STATE_RUNNABLE which reflect if the vcpu is paused or not.
@@ -1248,7 +1265,7 @@ KVM_MP_STATE_RUNNABLE which reflect if the vcpu is paused or not.
 4.39 KVM_SET_MP_STATE
 
 Capability: KVM_CAP_MP_STATE
-Architectures: x86, s390, arm, arm64
+Architectures: x86, s390, arm, arm64, riscv
 Type: vcpu ioctl
 Parameters: struct kvm_mp_state (in)
 Returns: 0 on success; -1 on error
@@ -1260,7 +1277,7 @@ On x86, this ioctl is only useful after KVM_CREATE_IRQCHIP. Without an
 in-kernel irqchip, the multiprocessing state must be maintained by userspace on
 these architectures.
 
-For arm/arm64:
+For arm/arm64/riscv:
 
 The only states that are valid are KVM_MP_STATE_STOPPED and
 KVM_MP_STATE_RUNNABLE which reflect if the vcpu should be paused or not.
@@ -2269,6 +2286,116 @@ following id bit patterns:
   0x7020 0000 0003 02 <0:3> <reg:5>
 
 
+RISC-V registers are mapped using the lower 32 bits. The upper 8 bits of
+that is the register group type.
+
+RISC-V config registers are meant for configuring a Guest VCPU and it has
+the following id bit patterns:
+  0x8020 0000 01 <index into the kvm_riscv_config struct:24> (32bit Host)
+  0x8030 0000 01 <index into the kvm_riscv_config struct:24> (64bit Host)
+
+Following are the RISC-V config registers:
+
+    Encoding            Register  Description
+------------------------------------------------------------------
+  0x80x0 0000 0100 0000 isa       ISA feature bitmap of Guest VCPU
+  0x80x0 0000 0100 0001 tbfreq    Time base frequency
+
+The isa config register can be read anytime but can only be written before
+a Guest VCPU runs. It will have ISA feature bits matching underlying host
+set by default. The tbfreq config register is a read-only register and it
+will return host timebase frequenc.
+
+RISC-V core registers represent the general excution state of a Guest VCPU
+and it has the following id bit patterns:
+  0x8020 0000 02 <index into the kvm_regs struct:24> (32bit Host)
+  0x8030 0000 02 <index into the kvm_regs struct:24> (64bit Host)
+
+Following are the RISC-V core registers:
+
+    Encoding            Register  Description
+------------------------------------------------------------------
+  0x80x0 0000 0200 0000 regs.pc   Program counter
+  0x80x0 0000 0200 0001 regs.ra   Return address
+  0x80x0 0000 0200 0002 regs.sp   Stack pointer
+  0x80x0 0000 0200 0003 regs.gp   Global pointer
+  0x80x0 0000 0200 0004 regs.tp   Task pointer
+  0x80x0 0000 0200 0005 regs.t0   Caller saved register 0
+  0x80x0 0000 0200 0006 regs.t1   Caller saved register 1
+  0x80x0 0000 0200 0007 regs.t2   Caller saved register 2
+  0x80x0 0000 0200 0008 regs.s0   Callee saved register 0
+  0x80x0 0000 0200 0009 regs.s1   Callee saved register 1
+  0x80x0 0000 0200 000a regs.a0   Function argument (or return value) 0
+  0x80x0 0000 0200 000b regs.a1   Function argument (or return value) 1
+  0x80x0 0000 0200 000c regs.a2   Function argument 2
+  0x80x0 0000 0200 000d regs.a3   Function argument 3
+  0x80x0 0000 0200 000e regs.a4   Function argument 4
+  0x80x0 0000 0200 000f regs.a5   Function argument 5
+  0x80x0 0000 0200 0010 regs.a6   Function argument 6
+  0x80x0 0000 0200 0011 regs.a7   Function argument 7
+  0x80x0 0000 0200 0012 regs.s2   Callee saved register 2
+  0x80x0 0000 0200 0013 regs.s3   Callee saved register 3
+  0x80x0 0000 0200 0014 regs.s4   Callee saved register 4
+  0x80x0 0000 0200 0015 regs.s5   Callee saved register 5
+  0x80x0 0000 0200 0016 regs.s6   Callee saved register 6
+  0x80x0 0000 0200 0017 regs.s7   Callee saved register 7
+  0x80x0 0000 0200 0018 regs.s8   Callee saved register 8
+  0x80x0 0000 0200 0019 regs.s9   Callee saved register 9
+  0x80x0 0000 0200 001a regs.s10  Callee saved register 10
+  0x80x0 0000 0200 001b regs.s11  Callee saved register 11
+  0x80x0 0000 0200 001c regs.t3   Caller saved register 3
+  0x80x0 0000 0200 001d regs.t4   Caller saved register 4
+  0x80x0 0000 0200 001e regs.t5   Caller saved register 5
+  0x80x0 0000 0200 001f regs.t6   Caller saved register 6
+  0x80x0 0000 0200 0020 mode      Privilege mode (1 = S-mode or 0 = U-mode)
+
+RISC-V csr registers represent the supervisor mode control/status registers
+of a Guest VCPU and it has the following id bit patterns:
+  0x8020 0000 03 <index into the kvm_sregs struct:24> (32bit Host)
+  0x8030 0000 03 <index into the kvm_sregs struct:24> (64bit Host)
+
+Following are the RISC-V csr registers:
+
+    Encoding            Register  Description
+------------------------------------------------------------------
+  0x80x0 0000 0300 0000 sstatus   Supervisor status
+  0x80x0 0000 0300 0001 sie       Supervisor interrupt enable
+  0x80x0 0000 0300 0002 stvec     Supervisor trap vector base
+  0x80x0 0000 0300 0003 sscratch  Supervisor scratch register
+  0x80x0 0000 0300 0004 sepc      Supervisor exception program counter
+  0x80x0 0000 0300 0005 scause    Supervisor trap cause
+  0x80x0 0000 0300 0006 stval     Supervisor bad address or instruction
+  0x80x0 0000 0300 0007 sip       Supervisor interrupt pending
+  0x80x0 0000 0300 0008 satp      Supervisor address translation and protection
+
+RISC-V F extension registers represent the single precision floating point
+state of a Guest VCPU and it has the following id bit patterns:
+  0x8020 0000 04 <index into the __riscv_f_ext_state struct:24>
+
+Following are the RISC-V F extension registers:
+
+    Encoding            Register  Description
+------------------------------------------------------------------
+  0x8020 0000 0400 0000 f[0]      Floating point register 0
+  ...
+  0x8020 0000 0400 001f f[31]     Floating point register 31
+  0x8020 0000 0400 0020 fcsr      Floating point control and status register
+
+RISC-V D extension registers represent the double precision floating point
+state of a Guest VCPU and it has the following id bit patterns:
+  0x8020 0000 05 <index into the __riscv_d_ext_state struct:24> (fcsr)
+  0x8030 0000 05 <index into the __riscv_d_ext_state struct:24> (non-fcsr)
+
+Following are the RISC-V D extension registers:
+
+    Encoding            Register  Description
+------------------------------------------------------------------
+  0x8030 0000 0500 0000 f[0]      Floating point register 0
+  ...
+  0x8030 0000 0500 001f f[31]     Floating point register 31
+  0x8020 0000 0500 0020 fcsr      Floating point control and status register
+
+
 4.69 KVM_GET_ONE_REG
 
 Capability: KVM_CAP_ONE_REG
-- 
2.17.1


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[PATCH v7 20/21] RISC-V: Enable VIRTIO drivers in RV64 and RV32 defconfig

[Anup Patel]

This patch enables more VIRTIO drivers (such as console, rpmsg, 9p,
rng, etc.) which are usable on KVM RISC-V Guest and Xvisor RISC-V
Guest.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
 arch/riscv/configs/defconfig      | 11 +++++++++++
 arch/riscv/configs/rv32_defconfig | 11 +++++++++++
 2 files changed, 22 insertions(+)

diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig
index 3efff552a261..420a0dbef386 100644
--- a/arch/riscv/configs/defconfig
+++ b/arch/riscv/configs/defconfig
@@ -29,6 +29,8 @@ CONFIG_IP_PNP_DHCP=y
 CONFIG_IP_PNP_BOOTP=y
 CONFIG_IP_PNP_RARP=y
 CONFIG_NETLINK_DIAG=y
+CONFIG_NET_9P=y
+CONFIG_NET_9P_VIRTIO=y
 CONFIG_PCI=y
 CONFIG_PCIEPORTBUS=y
 CONFIG_PCI_HOST_GENERIC=y
@@ -39,6 +41,7 @@ CONFIG_BLK_DEV_LOOP=y
 CONFIG_VIRTIO_BLK=y
 CONFIG_BLK_DEV_SD=y
 CONFIG_BLK_DEV_SR=y
+CONFIG_SCSI_VIRTIO=y
 CONFIG_ATA=y
 CONFIG_SATA_AHCI=y
 CONFIG_SATA_AHCI_PLATFORM=y
@@ -54,6 +57,7 @@ CONFIG_SERIAL_8250_CONSOLE=y
 CONFIG_SERIAL_OF_PLATFORM=y
 CONFIG_SERIAL_EARLYCON_RISCV_SBI=y
 CONFIG_HVC_RISCV_SBI=y
+CONFIG_VIRTIO_CONSOLE=y
 CONFIG_HW_RANDOM=y
 CONFIG_HW_RANDOM_VIRTIO=y
 CONFIG_SPI=y
@@ -61,6 +65,7 @@ CONFIG_SPI_SIFIVE=y
 # CONFIG_PTP_1588_CLOCK is not set
 CONFIG_DRM=y
 CONFIG_DRM_RADEON=y
+CONFIG_DRM_VIRTIO_GPU=y
 CONFIG_FRAMEBUFFER_CONSOLE=y
 CONFIG_USB=y
 CONFIG_USB_XHCI_HCD=y
@@ -73,7 +78,12 @@ CONFIG_USB_STORAGE=y
 CONFIG_USB_UAS=y
 CONFIG_MMC=y
 CONFIG_MMC_SPI=y
+CONFIG_VIRTIO_PCI=y
+CONFIG_VIRTIO_BALLOON=y
+CONFIG_VIRTIO_INPUT=y
 CONFIG_VIRTIO_MMIO=y
+CONFIG_RPMSG_CHAR=y
+CONFIG_RPMSG_VIRTIO=y
 CONFIG_EXT4_FS=y
 CONFIG_EXT4_FS_POSIX_ACL=y
 CONFIG_AUTOFS4_FS=y
@@ -86,6 +96,7 @@ CONFIG_NFS_V4=y
 CONFIG_NFS_V4_1=y
 CONFIG_NFS_V4_2=y
 CONFIG_ROOT_NFS=y
+CONFIG_9P_FS=y
 CONFIG_CRYPTO_USER_API_HASH=y
 CONFIG_CRYPTO_DEV_VIRTIO=y
 CONFIG_PRINTK_TIME=y
diff --git a/arch/riscv/configs/rv32_defconfig b/arch/riscv/configs/rv32_defconfig
index 7da93e494445..87ee6e62b64b 100644
--- a/arch/riscv/configs/rv32_defconfig
+++ b/arch/riscv/configs/rv32_defconfig
@@ -29,6 +29,8 @@ CONFIG_IP_PNP_DHCP=y
 CONFIG_IP_PNP_BOOTP=y
 CONFIG_IP_PNP_RARP=y
 CONFIG_NETLINK_DIAG=y
+CONFIG_NET_9P=y
+CONFIG_NET_9P_VIRTIO=y
 CONFIG_PCI=y
 CONFIG_PCIEPORTBUS=y
 CONFIG_PCI_HOST_GENERIC=y
@@ -39,6 +41,7 @@ CONFIG_BLK_DEV_LOOP=y
 CONFIG_VIRTIO_BLK=y
 CONFIG_BLK_DEV_SD=y
 CONFIG_BLK_DEV_SR=y
+CONFIG_SCSI_VIRTIO=y
 CONFIG_ATA=y
 CONFIG_SATA_AHCI=y
 CONFIG_SATA_AHCI_PLATFORM=y
@@ -54,11 +57,13 @@ CONFIG_SERIAL_8250_CONSOLE=y
 CONFIG_SERIAL_OF_PLATFORM=y
 CONFIG_SERIAL_EARLYCON_RISCV_SBI=y
 CONFIG_HVC_RISCV_SBI=y
+CONFIG_VIRTIO_CONSOLE=y
 CONFIG_HW_RANDOM=y
 CONFIG_HW_RANDOM_VIRTIO=y
 # CONFIG_PTP_1588_CLOCK is not set
 CONFIG_DRM=y
 CONFIG_DRM_RADEON=y
+CONFIG_DRM_VIRTIO_GPU=y
 CONFIG_FRAMEBUFFER_CONSOLE=y
 CONFIG_USB=y
 CONFIG_USB_XHCI_HCD=y
@@ -69,7 +74,12 @@ CONFIG_USB_OHCI_HCD=y
 CONFIG_USB_OHCI_HCD_PLATFORM=y
 CONFIG_USB_STORAGE=y
 CONFIG_USB_UAS=y
+CONFIG_VIRTIO_PCI=y
+CONFIG_VIRTIO_BALLOON=y
+CONFIG_VIRTIO_INPUT=y
 CONFIG_VIRTIO_MMIO=y
+CONFIG_RPMSG_CHAR=y
+CONFIG_RPMSG_VIRTIO=y
 CONFIG_SIFIVE_PLIC=y
 CONFIG_EXT4_FS=y
 CONFIG_EXT4_FS_POSIX_ACL=y
@@ -83,6 +93,7 @@ CONFIG_NFS_V4=y
 CONFIG_NFS_V4_1=y
 CONFIG_NFS_V4_2=y
 CONFIG_ROOT_NFS=y
+CONFIG_9P_FS=y
 CONFIG_CRYPTO_USER_API_HASH=y
 CONFIG_CRYPTO_DEV_VIRTIO=y
 CONFIG_PRINTK_TIME=y
-- 
2.17.1


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Re: [PATCH v7 20/21] RISC-V: Enable VIRTIO drivers in RV64 and RV32 defconfig

[Paul Walmsley]

On Wed, 4 Sep 2019, Anup Patel wrote:

> This patch enables more VIRTIO drivers (such as console, rpmsg, 9p,
> rng, etc.) which are usable on KVM RISC-V Guest and Xvisor RISC-V
> Guest.
> 
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> Acked-by: Paolo Bonzini <pbonzini@redhat.com>
> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> Reviewed-by: Alexander Graf <graf@amazon.com>

Thanks, queued for v5.4-rc.


- Paul

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[PATCH v7 21/21] RISC-V: KVM: Add MAINTAINERS entry

[Anup Patel]

Add myself as maintainer for KVM RISC-V and Atish as designated reviewer.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
---
 MAINTAINERS | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index e7a47b5210fd..71da7a4ea706 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8864,6 +8864,16 @@ F:	arch/powerpc/include/asm/kvm*
 F:	arch/powerpc/kvm/
 F:	arch/powerpc/kernel/kvm*
 
+KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)
+M:	Anup Patel <anup.patel@wdc.com>
+R:	Atish Patra <atish.patra@wdc.com>
+L:	kvm@vger.kernel.org
+T:	git git://github.com/kvm-riscv/linux.git
+S:	Maintained
+F:	arch/riscv/include/uapi/asm/kvm*
+F:	arch/riscv/include/asm/kvm*
+F:	arch/riscv/kvm/
+
 KERNEL VIRTUAL MACHINE for s390 (KVM/s390)
 M:	Christian Borntraeger <borntraeger@de.ibm.com>
 M:	Janosch Frank <frankja@linux.ibm.com>
-- 
2.17.1


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