From 358b28f09f0ab074d781df72b8a671edb1547789 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 20 Dec 2018 11:36:07 +0000 Subject: arm/arm64: KVM: Allow a VCPU to fully reset itself The current kvm_psci_vcpu_on implementation will directly try to manipulate the state of the VCPU to reset it. However, since this is not done on the thread that runs the VCPU, we can end up in a strangely corrupted state when the source and target VCPUs are running at the same time. Fix this by factoring out all reset logic from the PSCI implementation and forwarding the required information along with a request to the target VCPU. Reviewed-by: Andrew Jones Signed-off-by: Marc Zyngier Signed-off-by: Christoffer Dall --- arch/arm/include/asm/kvm_host.h | 10 ++++++++++ arch/arm/kvm/reset.c | 24 ++++++++++++++++++++++++ 2 files changed, 34 insertions(+) (limited to 'arch/arm') diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index ca56537b61bc..50e89869178a 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -48,6 +48,7 @@ #define KVM_REQ_SLEEP \ KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP) #define KVM_REQ_IRQ_PENDING KVM_ARCH_REQ(1) +#define KVM_REQ_VCPU_RESET KVM_ARCH_REQ(2) DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use); @@ -147,6 +148,13 @@ struct kvm_cpu_context { typedef struct kvm_cpu_context kvm_cpu_context_t; +struct vcpu_reset_state { + unsigned long pc; + unsigned long r0; + bool be; + bool reset; +}; + struct kvm_vcpu_arch { struct kvm_cpu_context ctxt; @@ -186,6 +194,8 @@ struct kvm_vcpu_arch { /* Cache some mmu pages needed inside spinlock regions */ struct kvm_mmu_memory_cache mmu_page_cache; + struct vcpu_reset_state reset_state; + /* Detect first run of a vcpu */ bool has_run_once; }; diff --git a/arch/arm/kvm/reset.c b/arch/arm/kvm/reset.c index 5ed0c3ee33d6..e53327912adc 100644 --- a/arch/arm/kvm/reset.c +++ b/arch/arm/kvm/reset.c @@ -26,6 +26,7 @@ #include #include #include +#include #include @@ -69,6 +70,29 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu) /* Reset CP15 registers */ kvm_reset_coprocs(vcpu); + /* + * Additional reset state handling that PSCI may have imposed on us. + * Must be done after all the sys_reg reset. + */ + if (READ_ONCE(vcpu->arch.reset_state.reset)) { + unsigned long target_pc = vcpu->arch.reset_state.pc; + + /* Gracefully handle Thumb2 entry point */ + if (target_pc & 1) { + target_pc &= ~1UL; + vcpu_set_thumb(vcpu); + } + + /* Propagate caller endianness */ + if (vcpu->arch.reset_state.be) + kvm_vcpu_set_be(vcpu); + + *vcpu_pc(vcpu) = target_pc; + vcpu_set_reg(vcpu, 0, vcpu->arch.reset_state.r0); + + vcpu->arch.reset_state.reset = false; + } + /* Reset arch_timer context */ return kvm_timer_vcpu_reset(vcpu); } -- cgit v1.2.3-59-g8ed1b From 20589c8cc47dce5854c8bf1b44a9fc63d798d26d Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 20 Dec 2018 13:07:40 +0000 Subject: arm/arm64: KVM: Don't panic on failure to properly reset system registers Failing to properly reset system registers is pretty bad. But not quite as bad as bringing the whole machine down... So warn loudly, but slightly more gracefully. Signed-off-by: Marc Zyngier Acked-by: Christoffer Dall --- arch/arm/kvm/coproc.c | 4 ++-- arch/arm64/kvm/sys_regs.c | 8 +++++--- 2 files changed, 7 insertions(+), 5 deletions(-) (limited to 'arch/arm') diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c index 222c1635bc7a..e8bd288fd5be 100644 --- a/arch/arm/kvm/coproc.c +++ b/arch/arm/kvm/coproc.c @@ -1450,6 +1450,6 @@ void kvm_reset_coprocs(struct kvm_vcpu *vcpu) reset_coproc_regs(vcpu, table, num); for (num = 1; num < NR_CP15_REGS; num++) - if (vcpu_cp15(vcpu, num) == 0x42424242) - panic("Didn't reset vcpu_cp15(vcpu, %zi)", num); + WARN(vcpu_cp15(vcpu, num) == 0x42424242, + "Didn't reset vcpu_cp15(vcpu, %zi)", num); } diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 86096774abcd..c936aa40c3f4 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -2608,7 +2608,9 @@ void kvm_reset_sys_regs(struct kvm_vcpu *vcpu) table = get_target_table(vcpu->arch.target, true, &num); reset_sys_reg_descs(vcpu, table, num); - for (num = 1; num < NR_SYS_REGS; num++) - if (__vcpu_sys_reg(vcpu, num) == 0x4242424242424242) - panic("Didn't reset __vcpu_sys_reg(%zi)", num); + for (num = 1; num < NR_SYS_REGS; num++) { + if (WARN(__vcpu_sys_reg(vcpu, num) == 0x4242424242424242, + "Didn't reset __vcpu_sys_reg(%zi)\n", num)) + break; + } } -- cgit v1.2.3-59-g8ed1b From 309a205688060fbb000e9402078cf53cebde0793 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Sat, 2 Feb 2019 12:14:03 +0000 Subject: arm: KVM: Add missing kvm_stage2_has_pmd() helper Fixup 32bit by providing the now required helper. Cc: Suzuki Poulose Signed-off-by: Marc Zyngier --- arch/arm/include/asm/stage2_pgtable.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/arm') diff --git a/arch/arm/include/asm/stage2_pgtable.h b/arch/arm/include/asm/stage2_pgtable.h index c4b1d4fb1797..de2089501b8b 100644 --- a/arch/arm/include/asm/stage2_pgtable.h +++ b/arch/arm/include/asm/stage2_pgtable.h @@ -76,4 +76,9 @@ static inline bool kvm_stage2_has_pud(struct kvm *kvm) #define S2_PMD_MASK PMD_MASK #define S2_PMD_SIZE PMD_SIZE +static inline bool kvm_stage2_has_pmd(struct kvm *kvm) +{ + return true; +} + #endif /* __ARM_S2_PGTABLE_H_ */ -- cgit v1.2.3-59-g8ed1b