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KVM: arm64: Make kvm_skip_instr() and co private to HYP

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In an effort to remove the vcpu PC manipulations from EL1 on nVHE
systems, move kvm_skip_instr() to be HYP-specific. EL1's intent
to increment PC post emulation is now signalled via a flag in the
vcpu structure.

Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Marc Zyngier 2020-10-14 09:29:27 +01:00
parent 6ddbc281e2
commit cdb5e02ed1
12 changed files with 77 additions and 31 deletions
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27
arch/arm64/include/asm/kvm_emulate.h
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@ -472,32 +472,9 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu,
return data; /* Leave LE untouched */
}
static __always_inline void kvm_skip_instr(struct kvm_vcpu *vcpu)
static __always_inline void kvm_incr_pc(struct kvm_vcpu *vcpu)
{
if (vcpu_mode_is_32bit(vcpu)) {
kvm_skip_instr32(vcpu);
} else {
*vcpu_pc(vcpu) += 4;
*vcpu_cpsr(vcpu) &= ~PSR_BTYPE_MASK;
}
/* advance the singlestep state machine */
*vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS;
}
/*
* Skip an instruction which has been emulated at hyp while most guest sysregs
* are live.
*/
static __always_inline void __kvm_skip_instr(struct kvm_vcpu *vcpu)
{
*vcpu_pc(vcpu) = read_sysreg_el2(SYS_ELR);
vcpu_gp_regs(vcpu)->pstate = read_sysreg_el2(SYS_SPSR);
kvm_skip_instr(vcpu);
write_sysreg_el2(vcpu_gp_regs(vcpu)->pstate, SYS_SPSR);
write_sysreg_el2(*vcpu_pc(vcpu), SYS_ELR);
vcpu->arch.flags |= KVM_ARM64_INCREMENT_PC;
}
#endif /* __ARM64_KVM_EMULATE_H__ */

1
arch/arm64/include/asm/kvm_host.h
View File

@ -407,6 +407,7 @@ struct kvm_vcpu_arch {
#define KVM_ARM64_GUEST_HAS_SVE (1 << 5) /* SVE exposed to guest */
#define KVM_ARM64_VCPU_SVE_FINALIZED (1 << 6) /* SVE config completed */
#define KVM_ARM64_GUEST_HAS_PTRAUTH (1 << 7) /* PTRAUTH exposed to guest */
#define KVM_ARM64_INCREMENT_PC (1 << 8) /* Increment PC */
#define vcpu_has_sve(vcpu) (system_supports_sve() && \
((vcpu)->arch.flags & KVM_ARM64_GUEST_HAS_SVE))

6
arch/arm64/kvm/handle_exit.c
View File

@ -61,7 +61,7 @@ static int handle_smc(struct kvm_vcpu *vcpu)
* otherwise return to the same address...
*/
vcpu_set_reg(vcpu, 0, ~0UL);
kvm_skip_instr(vcpu);
kvm_incr_pc(vcpu);
return 1;
}
@ -100,7 +100,7 @@ static int kvm_handle_wfx(struct kvm_vcpu *vcpu)
kvm_clear_request(KVM_REQ_UNHALT, vcpu);
}
kvm_skip_instr(vcpu);
kvm_incr_pc(vcpu);
return 1;
}
@ -221,7 +221,7 @@ static int handle_trap_exceptions(struct kvm_vcpu *vcpu)
* that fail their condition code check"
*/
if (!kvm_condition_valid(vcpu)) {
kvm_skip_instr(vcpu);
kvm_incr_pc(vcpu);
handled = 1;
} else {
exit_handle_fn exit_handler;

56
arch/arm64/kvm/hyp/include/hyp/adjust_pc.h Normal file
View File

@ -0,0 +1,56 @@
// SPDX-License-Identifier: GPL-2.0-only
/*
* Guest PC manipulation helpers
*
* Copyright (C) 2012,2013 - ARM Ltd
* Copyright (C) 2020 - Google LLC
* Author: Marc Zyngier <maz@kernel.org>
*/
#ifndef __ARM64_KVM_HYP_ADJUST_PC_H__
#define __ARM64_KVM_HYP_ADJUST_PC_H__
#include <asm/kvm_emulate.h>
#include <asm/kvm_host.h>
static inline void kvm_skip_instr(struct kvm_vcpu *vcpu)
{
if (vcpu_mode_is_32bit(vcpu)) {
kvm_skip_instr32(vcpu);
} else {
*vcpu_pc(vcpu) += 4;
*vcpu_cpsr(vcpu) &= ~PSR_BTYPE_MASK;
}
/* advance the singlestep state machine */
*vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS;
}
/*
* Skip an instruction which has been emulated at hyp while most guest sysregs
* are live.
*/
static inline void __kvm_skip_instr(struct kvm_vcpu *vcpu)
{
*vcpu_pc(vcpu) = read_sysreg_el2(SYS_ELR);
vcpu_gp_regs(vcpu)->pstate = read_sysreg_el2(SYS_SPSR);
kvm_skip_instr(vcpu);
write_sysreg_el2(vcpu_gp_regs(vcpu)->pstate, SYS_SPSR);
write_sysreg_el2(*vcpu_pc(vcpu), SYS_ELR);
}
/*
* Adjust the guest PC on entry, depending on flags provided by EL1
* for the purpose of emulation (MMIO, sysreg).
*/
static inline void __adjust_pc(struct kvm_vcpu *vcpu)
{
if (vcpu->arch.flags & KVM_ARM64_INCREMENT_PC) {
kvm_skip_instr(vcpu);
vcpu->arch.flags &= ~KVM_ARM64_INCREMENT_PC;
}
}
#endif

2
arch/arm64/kvm/hyp/include/hyp/switch.h
View File

@ -7,6 +7,8 @@
#ifndef __ARM64_KVM_HYP_SWITCH_H__
#define __ARM64_KVM_HYP_SWITCH_H__
#include <hyp/adjust_pc.h>
#include <linux/arm-smccc.h>
#include <linux/kvm_host.h>
#include <linux/types.h>

3
arch/arm64/kvm/hyp/nvhe/switch.c
View File

@ -4,6 +4,7 @@
* Author: Marc Zyngier <marc.zyngier@arm.com>
*/
#include <hyp/adjust_pc.h>
#include <hyp/switch.h>
#include <hyp/sysreg-sr.h>
@ -189,6 +190,8 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
__sysreg_save_state_nvhe(host_ctxt);
__adjust_pc(vcpu);
/*
* We must restore the 32-bit state before the sysregs, thanks
* to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).

2
arch/arm64/kvm/hyp/vgic-v2-cpuif-proxy.c
View File

@ -4,6 +4,8 @@
* Author: Marc Zyngier <marc.zyngier@arm.com>
*/
#include <hyp/adjust_pc.h>
#include <linux/compiler.h>
#include <linux/irqchip/arm-gic.h>
#include <linux/kvm_host.h>

2
arch/arm64/kvm/hyp/vgic-v3-sr.c
View File

@ -4,6 +4,8 @@
* Author: Marc Zyngier <marc.zyngier@arm.com>
*/
#include <hyp/adjust_pc.h>
#include <linux/compiler.h>
#include <linux/irqchip/arm-gic-v3.h>
#include <linux/kvm_host.h>

3
arch/arm64/kvm/hyp/vhe/switch.c
View File

@ -4,6 +4,7 @@
* Author: Marc Zyngier <marc.zyngier@arm.com>
*/
#include <hyp/adjust_pc.h>
#include <hyp/switch.h>
#include <linux/arm-smccc.h>
@ -133,6 +134,8 @@ static int __kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
__load_guest_stage2(vcpu->arch.hw_mmu);
__activate_traps(vcpu);
__adjust_pc(vcpu);
sysreg_restore_guest_state_vhe(guest_ctxt);
__debug_switch_to_guest(vcpu);

2
arch/arm64/kvm/mmio.c
View File

@ -115,7 +115,7 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu)
* The MMIO instruction is emulated and should not be re-executed
* in the guest.
*/
kvm_skip_instr(vcpu);
kvm_incr_pc(vcpu);
return 0;
}

2
arch/arm64/kvm/mmu.c
View File

@ -1014,7 +1014,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
* cautious, and skip the instruction.
*/
if (kvm_is_error_hva(hva) && kvm_vcpu_dabt_is_cm(vcpu)) {
kvm_skip_instr(vcpu);
kvm_incr_pc(vcpu);
ret = 1;
goto out_unlock;
}

2
arch/arm64/kvm/sys_regs.c
View File

@ -2199,7 +2199,7 @@ static void perform_access(struct kvm_vcpu *vcpu,
/* Skip instruction if instructed so */
if (likely(r->access(vcpu, params, r)))
kvm_skip_instr(vcpu);
kvm_incr_pc(vcpu);
}
/*