From: Anup Patel <Anup.Patel@wdc.com>
To: Palmer Dabbelt <palmer@sifive.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Paolo Bonzini <pbonzini@redhat.com>, Radim K <rkrcmar@redhat.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Atish Patra <Atish.Patra@wdc.com>,
Alistair Francis <Alistair.Francis@wdc.com>,
Damien Le Moal <Damien.LeMoal@wdc.com>,
Christoph Hellwig <hch@infradead.org>,
Anup Patel <anup@brainfault.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Anup Patel <Anup.Patel@wdc.com>
Subject: [PATCH v6 11/21] RISC-V: KVM: Handle WFI exits for VCPU
Date: Thu, 29 Aug 2019 13:56:24 +0000 [thread overview]
Message-ID: <20190829135427.47808-12-anup.patel@wdc.com> (raw)
In-Reply-To: <20190829135427.47808-1-anup.patel@wdc.com>
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 | 71 ++++++++++++++++++++++++++++++++++++++
1 file changed, 71 insertions(+)
diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
index 700d8158e55b..321062fff65b 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 +119,66 @@
(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, ut_stval = 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,
+ &ut_stval);
+ if (ut_scause) {
+ kvm_riscv_vcpu_trap_redirect(vcpu, ut_scause,
+ ut_stval);
+ 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)
{
@@ -507,6 +574,10 @@ 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
next prev parent reply other threads:[~2019-08-29 13:56 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-29 13:55 [PATCH v6 00/21] KVM RISC-V Support Anup Patel
2019-08-29 13:55 ` [PATCH v6 01/21] KVM: RISC-V: Add KVM_REG_RISCV for ONE_REG interface Anup Patel
2019-08-29 13:55 ` [PATCH v6 02/21] RISC-V: Add bitmap reprensenting ISA features common across CPUs Anup Patel
2019-08-29 13:55 ` [PATCH v6 03/21] RISC-V: Export few kernel symbols Anup Patel
2019-08-29 13:55 ` [PATCH v6 04/21] RISC-V: Add hypervisor extension related CSR defines Anup Patel
2019-08-29 13:55 ` [PATCH v6 05/21] RISC-V: Add initial skeletal KVM support Anup Patel
2019-08-29 13:55 ` [PATCH v6 06/21] RISC-V: KVM: Implement VCPU create, init and destroy functions Anup Patel
2019-08-29 13:55 ` [PATCH v6 07/21] RISC-V: KVM: Implement VCPU interrupts and requests handling Anup Patel
2019-08-29 13:56 ` [PATCH v6 08/21] RISC-V: KVM: Implement KVM_GET_ONE_REG/KVM_SET_ONE_REG ioctls Anup Patel
2019-08-29 13:56 ` [PATCH v6 09/21] RISC-V: KVM: Implement VCPU world-switch Anup Patel
2019-08-29 13:56 ` [PATCH v6 10/21] RISC-V: KVM: Handle MMIO exits for VCPU Anup Patel
2019-09-03 8:58 ` Andrew Jones
2019-09-03 9:26 ` Anup Patel
2019-09-03 9:33 ` Anup Patel
2019-08-29 13:56 ` Anup Patel [this message]
2019-08-29 13:56 ` [PATCH v6 12/21] RISC-V: KVM: Implement VMID allocator Anup Patel
2019-08-29 13:56 ` [PATCH v6 13/21] RISC-V: KVM: Implement stage2 page table programming Anup Patel
2019-08-29 13:56 ` [PATCH v6 14/21] RISC-V: KVM: Implement MMU notifiers Anup Patel
2019-08-29 13:56 ` [PATCH v6 15/21] RISC-V: KVM: Add timer functionality Anup Patel
2019-08-29 13:56 ` [PATCH v6 16/21] RISC-V: KVM: FP lazy save/restore Anup Patel
2019-08-29 13:57 ` [PATCH v6 17/21] RISC-V: KVM: Implement ONE REG interface for FP registers Anup Patel
2019-08-29 13:57 ` [PATCH v6 18/21] RISC-V: KVM: Add SBI v0.1 support Anup Patel
2019-08-29 13:57 ` [PATCH v6 19/21] RISC-V: KVM: Document RISC-V specific parts of KVM API Anup Patel
2019-09-03 9:53 ` Anup Patel
2019-08-29 13:57 ` [PATCH v6 20/21] RISC-V: Enable VIRTIO drivers in RV64 and RV32 defconfig Anup Patel
2019-08-29 13:57 ` [PATCH v6 21/21] RISC-V: KVM: Add MAINTAINERS entry Anup Patel
2019-09-04 3:39 ` Anup Patel
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