From 325f9c649c8a4e447e4d3babacc7a60b75012d5d Mon Sep 17 00:00:00 2001 From: Andrew Jones Date: Sun, 4 Jun 2017 14:43:59 +0200 Subject: [PATCH] KVM: arm/arm64: use vcpu requests for irq injection Don't use request-less VCPU kicks when injecting IRQs, as a VCPU kick meant to trigger the interrupt injection could be sent while the VCPU is outside guest mode, which means no IPI is sent, and after it has called kvm_vgic_flush_hwstate(), meaning it won't see the updated GIC state until its next exit some time later for some other reason. The receiving VCPU only needs to check this request in VCPU RUN to handle it. By checking it, if it's pending, a memory barrier will be issued that ensures all state is visible. See "Ensuring Requests Are Seen" of Documentation/virtual/kvm/vcpu-requests.rst Signed-off-by: Andrew Jones Reviewed-by: Christoffer Dall Signed-off-by: Christoffer Dall --- arch/arm/include/asm/kvm_host.h | 1 + arch/arm64/include/asm/kvm_host.h | 1 + virt/kvm/arm/arm.c | 7 +++++++ virt/kvm/arm/vgic/vgic.c | 9 +++++++-- 4 files changed, 16 insertions(+), 2 deletions(-) diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index fdd644c01c89..00ad56ee6455 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -46,6 +46,7 @@ #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) u32 *kvm_vcpu_reg(struct kvm_vcpu *vcpu, u8 reg_num, u32 mode); int __attribute_const__ kvm_target_cpu(void); diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 9bd0d1040de9..0c4fd1f46e10 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -43,6 +43,7 @@ #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) int __attribute_const__ kvm_target_cpu(void); int kvm_reset_vcpu(struct kvm_vcpu *vcpu); diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c index ddc833987dfb..cac5c2f2ddba 100644 --- a/virt/kvm/arm/arm.c +++ b/virt/kvm/arm/arm.c @@ -580,6 +580,12 @@ static void check_vcpu_requests(struct kvm_vcpu *vcpu) if (kvm_request_pending(vcpu)) { if (kvm_check_request(KVM_REQ_SLEEP, vcpu)) vcpu_req_sleep(vcpu); + + /* + * Clear IRQ_PENDING requests that were made to guarantee + * that a VCPU sees new virtual interrupts. + */ + kvm_check_request(KVM_REQ_IRQ_PENDING, vcpu); } } @@ -771,6 +777,7 @@ static int vcpu_interrupt_line(struct kvm_vcpu *vcpu, int number, bool level) * trigger a world-switch round on the running physical CPU to set the * virtual IRQ/FIQ fields in the HCR appropriately. */ + kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu); kvm_vcpu_kick(vcpu); return 0; diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c index aea080a2c443..c66feaca2a5d 100644 --- a/virt/kvm/arm/vgic/vgic.c +++ b/virt/kvm/arm/vgic/vgic.c @@ -286,8 +286,10 @@ retry: * won't see this one until it exits for some other * reason. */ - if (vcpu) + if (vcpu) { + kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu); kvm_vcpu_kick(vcpu); + } return false; } @@ -333,6 +335,7 @@ retry: spin_unlock(&irq->irq_lock); spin_unlock(&vcpu->arch.vgic_cpu.ap_list_lock); + kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu); kvm_vcpu_kick(vcpu); return true; @@ -722,8 +725,10 @@ void vgic_kick_vcpus(struct kvm *kvm) * a good kick... */ kvm_for_each_vcpu(c, vcpu, kvm) { - if (kvm_vgic_vcpu_pending_irq(vcpu)) + if (kvm_vgic_vcpu_pending_irq(vcpu)) { + kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu); kvm_vcpu_kick(vcpu); + } } } -- 2.20.1