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From: Andrew Scull <ascull@google.com>
To: kvmarm@lists.cs.columbia.edu
Cc: maz@kernel.org, kernel-team@android.com
Subject: [PATCH 11/37] KVM: arm64: nVHE: Migrate hyp-init to SMCCC
Date: Wed, 15 Jul 2020 19:44:12 +0100
Message-ID: <20200715184438.1390996-12-ascull@google.com> (raw)
In-Reply-To: <20200715184438.1390996-1-ascull@google.com>

To complete the transition to SMCCC, the hyp initialization is given a
function ID. This looks neater than comparing the hyp stub function IDs
to the page table physical address.

Some care is taken to only clobber x0-3 before the host context is saved
as only those registers can be clobbered accoring to SMCCC. Fortunately,
only a few acrobatics are needed. The possible new tpidr_el2 is moved to
the argument in x2 so that it can be stashed in tpidr_el2 early to free
up a scratch register. The page table configuration then makes use of
x0-2.

Signed-off-by: Andrew Scull <ascull@google.com>
---
 arch/arm64/include/asm/kvm_host.h  |  6 ---
 arch/arm64/kvm/Makefile            |  2 +-
 arch/arm64/kvm/arm.c               |  7 +++-
 arch/arm64/kvm/hyp.S               | 23 -----------
 arch/arm64/kvm/hyp/nvhe/hyp-init.S | 63 +++++++++++++++++-------------
 arch/arm64/kvm/hyp/nvhe/hyp-main.c |  6 +++
 6 files changed, 48 insertions(+), 59 deletions(-)
 delete mode 100644 arch/arm64/kvm/hyp.S

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 5603d2f465eb..152c050e74a9 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -493,12 +493,6 @@ int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);
 void kvm_arm_halt_guest(struct kvm *kvm);
 void kvm_arm_resume_guest(struct kvm *kvm);
 
-u64 __kvm_call_hyp_init(phys_addr_t pgd_ptr,
-			unsigned long hyp_stack_ptr,
-			unsigned long vector_ptr,
-			unsigned long start_hyp,
-			unsigned long tpidr_el2);
-
 #define kvm_call_hyp_nvhe(f, ...)						\
 	({								\
 		struct arm_smccc_res res;				\
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index 99977c1972cc..1504c81fbf5d 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -13,7 +13,7 @@ obj-$(CONFIG_KVM) += hyp/
 kvm-y := $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o \
 	 $(KVM)/vfio.o $(KVM)/irqchip.o \
 	 arm.o mmu.o mmio.o psci.o perf.o hypercalls.o pvtime.o \
-	 inject_fault.o regmap.o va_layout.o hyp.o handle_exit.o \
+	 inject_fault.o regmap.o va_layout.o handle_exit.o \
 	 guest.o debug.o reset.o sys_regs.o \
 	 vgic-sys-reg-v3.o fpsimd.o pmu.o \
 	 aarch32.o arch_timer.o \
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index c42c00c8141a..fe49203948d3 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1265,6 +1265,7 @@ static void cpu_init_hyp_mode(void)
 	unsigned long vector_ptr;
 	unsigned long start_hyp;
 	unsigned long tpidr_el2;
+	struct arm_smccc_res res;
 
 	/* Switch from the HYP stub to our own HYP init vector */
 	__hyp_set_vectors(kvm_get_idmap_vector());
@@ -1290,8 +1291,10 @@ static void cpu_init_hyp_mode(void)
 	 * cpus_have_const_cap() wrapper.
 	 */
 	BUG_ON(!system_capabilities_finalized());
-	__kvm_call_hyp_init(pgd_ptr, hyp_stack_ptr, vector_ptr, start_hyp,
-			    tpidr_el2);
+	arm_smccc_1_1_hvc(KVM_HOST_SMCCC_FUNC(__kvm_hyp_init),
+			  pgd_ptr, tpidr_el2, start_hyp, hyp_stack_ptr,
+			  vector_ptr, &res);
+	WARN_ON(res.a0 != SMCCC_RET_SUCCESS);
 
 	/*
 	 * Disabling SSBD on a non-VHE system requires us to enable SSBS
diff --git a/arch/arm64/kvm/hyp.S b/arch/arm64/kvm/hyp.S
deleted file mode 100644
index 0891625c8648..000000000000
--- a/arch/arm64/kvm/hyp.S
+++ /dev/null
@@ -1,23 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Copyright (C) 2012,2013 - ARM Ltd
- * Author: Marc Zyngier <marc.zyngier@arm.com>
- */
-
-#include <linux/linkage.h>
-
-#include <asm/alternative.h>
-#include <asm/assembler.h>
-#include <asm/cpufeature.h>
-
-/*
- * u64 __kvm_call_hyp_init(phys_addr_t pgd_ptr,
- * 			   unsigned long hyp_stack_ptr,
- * 			   unsigned long vector_ptr,
- * 			   unsigned long start_hyp,
- * 			   unsigned long tpidr_el2);
- */
-SYM_FUNC_START(__kvm_call_hyp_init)
-	hvc	#0
-	ret
-SYM_FUNC_END(__kvm_call_hyp_init)
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-init.S b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
index 029c51365d03..df2a7904a83b 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-init.S
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-init.S
@@ -4,10 +4,12 @@
  * Author: Marc Zyngier <marc.zyngier@arm.com>
  */
 
+#include <linux/arm-smccc.h>
 #include <linux/linkage.h>
 
 #include <asm/assembler.h>
 #include <asm/kvm_arm.h>
+#include <asm/kvm_asm.h>
 #include <asm/kvm_mmu.h>
 #include <asm/pgtable-hwdef.h>
 #include <asm/sysreg.h>
@@ -43,31 +45,38 @@ __invalid:
 	b	.
 
 	/*
-	 * x0: HYP pgd
-	 * x1: HYP stack
-	 * x2: HYP vectors
+	 * x0: SMCCC function ID
+	 * x1: HYP pgd
+	 * x2: per-CPU offset
 	 * x3: __kvm_hyp_start HYP address
-	 * x4: per-CPU offset
+	 * x4: HYP stack
+	 * x5: HYP vectors
 	 */
 __do_hyp_init:
 	/* Check for a stub HVC call */
 	cmp	x0, #HVC_STUB_HCALL_NR
 	b.lo	__kvm_handle_stub_hvc
 
-	/* Set tpidr_el2 for use by HYP */
-	msr	tpidr_el2, x4
+	/* Set tpidr_el2 for use by HYP to free a register */
+	msr	tpidr_el2, x2
 
-	phys_to_ttbr x4, x0
+	mov	x2, #KVM_HOST_SMCCC_FUNC(__kvm_hyp_init)
+	cmp	x0, x2
+	b.eq	1f
+	mov	x0, #SMCCC_RET_NOT_SUPPORTED
+	eret
+
+1:	phys_to_ttbr x0, x1
 alternative_if ARM64_HAS_CNP
-	orr	x4, x4, #TTBR_CNP_BIT
+	orr	x0, x0, #TTBR_CNP_BIT
 alternative_else_nop_endif
-	msr	ttbr0_el2, x4
+	msr	ttbr0_el2, x0
 
-	mrs	x4, tcr_el1
-	mov_q	x5, TCR_EL2_MASK
-	and	x4, x4, x5
-	mov	x5, #TCR_EL2_RES1
-	orr	x4, x4, x5
+	mrs	x0, tcr_el1
+	mov_q	x1, TCR_EL2_MASK
+	and	x0, x0, x1
+	mov	x1, #TCR_EL2_RES1
+	orr	x0, x0, x1
 
 	/*
 	 * The ID map may be configured to use an extended virtual address
@@ -83,18 +92,18 @@ alternative_else_nop_endif
 	 *
 	 * So use the same T0SZ value we use for the ID map.
 	 */
-	ldr_l	x5, idmap_t0sz
-	bfi	x4, x5, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
+	ldr_l	x1, idmap_t0sz
+	bfi	x0, x1, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
 
 	/*
 	 * Set the PS bits in TCR_EL2.
 	 */
-	tcr_compute_pa_size x4, #TCR_EL2_PS_SHIFT, x5, x6
+	tcr_compute_pa_size x0, #TCR_EL2_PS_SHIFT, x1, x2
 
-	msr	tcr_el2, x4
+	msr	tcr_el2, x0
 
-	mrs	x4, mair_el1
-	msr	mair_el2, x4
+	mrs	x0, mair_el1
+	msr	mair_el2, x0
 	isb
 
 	/* Invalidate the stale TLBs from Bootloader */
@@ -106,19 +115,19 @@ alternative_else_nop_endif
 	 * as well as the EE bit on BE. Drop the A flag since the compiler
 	 * is allowed to generate unaligned accesses.
 	 */
-	mov_q	x4, (SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A))
-CPU_BE(	orr	x4, x4, #SCTLR_ELx_EE)
+	mov_q	x0, (SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A))
+CPU_BE(	orr	x0, x0, #SCTLR_ELx_EE)
 alternative_if ARM64_HAS_ADDRESS_AUTH
-	mov_q	x5, (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | \
+	mov_q	x1, (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | \
 		     SCTLR_ELx_ENDA | SCTLR_ELx_ENDB)
-	orr	x4, x4, x5
+	orr	x0, x0, x1
 alternative_else_nop_endif
-	msr	sctlr_el2, x4
+	msr	sctlr_el2, x0
 	isb
 
 	/* Set the stack and new vectors */
-	mov	sp, x1
-	msr	vbar_el2, x2
+	mov	sp, x4
+	msr	vbar_el2, x5
 
 	/* Leave the idmap posthaste and head over to __kvm_hyp_start */
 	br	x3
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 7e7c074f8093..4e3634cdfde6 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -125,6 +125,12 @@ void __noreturn kvm_hyp_main(void)
 	host_vcpu->arch.flags = KVM_ARM64_HOST_VCPU_FLAGS;
 	host_vcpu->arch.workaround_flags = VCPU_WORKAROUND_2_FLAG;
 
+	/*
+	 * The first time entering the host is seen by the host as the return
+	 * of the initialization HVC so mark it as successful.
+	 */
+	smccc_set_retval(host_vcpu, SMCCC_RET_SUCCESS, 0, 0, 0);
+
 	while (true) {
 		u64 exit_code;
 
-- 
2.27.0.389.gc38d7665816-goog

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  parent reply index

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-15 18:44 [PATCH 00/37] Transform the host into a vCPU Andrew Scull
2020-07-15 18:44 ` [PATCH 01/37] smccc: Make constants available to assembly Andrew Scull
2020-07-15 18:44 ` [PATCH 02/37] KVM: arm64: Move clearing of vcpu debug dirty bit Andrew Scull
2020-07-15 18:44 ` [PATCH 03/37] KVM: arm64: Track running vCPU outside of the CPU context Andrew Scull
2020-07-15 18:44 ` [PATCH 04/37] KVM: arm64: nVHE: Pass pointers consistently to hyp-init Andrew Scull
2020-07-15 18:44 ` [PATCH 05/37] KVM: arm64: nVHE: Break out of the hyp-init idmap Andrew Scull
2020-07-15 18:44 ` [PATCH 06/37] KVM: arm64: Only check pending interrupts if it would trap Andrew Scull
2020-07-17 16:21   ` Marc Zyngier
2020-07-15 18:44 ` [PATCH 07/37] KVM: arm64: Separate SError detection from VAXorcism Andrew Scull
2020-07-18  9:00   ` Marc Zyngier
2020-07-20 14:13     ` Andrew Scull
2020-07-20 14:56       ` Marc Zyngier
2020-07-23  0:59         ` FW: " Renters Cancellation Requests
2020-07-20 15:40   ` Andrew Scull
2020-07-20 15:57     ` Marc Zyngier
2020-07-15 18:44 ` [PATCH 08/37] KVM: arm64: nVHE: Introduce a hyp run loop for the host Andrew Scull
2020-07-15 18:44 ` [PATCH 09/37] smccc: Cast arguments to unsigned long Andrew Scull
2020-07-15 18:44 ` [PATCH 10/37] KVM: arm64: nVHE: Migrate hyp interface to SMCCC Andrew Scull
2020-07-15 18:44 ` Andrew Scull [this message]
2020-07-15 18:44 ` [PATCH 12/37] KVM: arm64: nVHE: Fix pointers during SMCCC convertion Andrew Scull
2020-07-15 18:44 ` [PATCH 13/37] KVM: arm64: Rename workaround 2 helpers Andrew Scull
2020-07-15 18:44 ` [PATCH 14/37] KVM: arm64: nVHE: Use __kvm_vcpu_run for the host vcpu Andrew Scull
2020-07-15 18:44 ` [PATCH 15/37] KVM: arm64: Share some context save and restore macros Andrew Scull
2020-07-15 18:44 ` [PATCH 16/37] KVM: arm64: nVHE: Handle stub HVCs in the host loop Andrew Scull
2020-07-15 18:44 ` [PATCH 17/37] KVM: arm64: nVHE: Store host sysregs in host vcpu Andrew Scull
2020-07-15 18:44 ` [PATCH 18/37] KVM: arm64: nVHE: Access pmu_events directly in kvm_host_data Andrew Scull
2020-07-15 18:44 ` [PATCH 19/37] KVM: arm64: nVHE: Drop host_ctxt argument for context switching Andrew Scull
2020-07-15 18:44 ` [PATCH 20/37] KVM: arm64: nVHE: Use host vcpu context for host debug state Andrew Scull
2020-07-15 18:44 ` [PATCH 21/37] KVM: arm64: Move host debug state from vcpu to percpu Andrew Scull
2020-07-15 18:44 ` [PATCH 22/37] KVM: arm64: nVHE: Store host's mdcr_el2 and hcr_el2 in its vcpu Andrew Scull
2020-07-15 18:44 ` [PATCH 23/37] KVM: arm64: Skip __hyp_panic and go direct to hyp_panic Andrew Scull
2020-07-15 18:44 ` [PATCH 24/37] KVM: arm64: Break apart kvm_host_data Andrew Scull
2020-07-15 18:44 ` [PATCH 25/37] KVM: arm64: nVHE: Unify sysreg state saving paths Andrew Scull
2020-07-15 18:44 ` [PATCH 26/37] KVM: arm64: nVHE: Unify 32-bit sysreg " Andrew Scull
2020-07-15 18:44 ` [PATCH 27/37] KVM: arm64: nVHE: Unify vgic save and restore Andrew Scull
2020-07-15 18:44 ` [PATCH 28/37] KVM: arm64: nVHE: Unify fpexc32 saving paths Andrew Scull
2020-07-15 18:44 ` [PATCH 29/37] KVM: arm64: nVHE: Separate the save and restore of debug state Andrew Scull
2020-07-15 18:44 ` [PATCH 30/37] KVM: arm64: nVHE: Remove MMU assumption in speculative AT workaround Andrew Scull
2020-07-15 18:44 ` [PATCH 31/37] KVM: arm64: Move speculative AT ISBs into context Andrew Scull
2020-07-15 18:44 ` [PATCH 32/37] KVM: arm64: nVHE: Unify sysreg state restoration paths Andrew Scull
2020-07-15 18:44 ` [PATCH 33/37] KVM: arm64: Remove __activate_vm wrapper Andrew Scull
2020-07-15 18:44 ` [PATCH 34/37] KVM: arm64: nVHE: Unify timer restore paths Andrew Scull
2020-07-15 18:44 ` [PATCH 35/37] KVM: arm64: nVHE: Unify PMU event restoration paths Andrew Scull
2020-07-15 18:44 ` [PATCH 36/37] KVM: arm64: nVHE: Unify GIC PMR " Andrew Scull
2020-07-15 18:44 ` [PATCH 37/37] KVM: arm64: Separate save and restore of vcpu trap state Andrew Scull

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