diff mbox series

[v2,2/2] LoongArch: KVM: Invalid guest steal time address on vCPU reset

Message ID 20240815071545.925867-3-maobibo@loongson.cn (mailing list archive)
State New, archived
Headers show
Series LoongArch: KVM: Fix some VM reboot issues | expand

Commit Message

Bibo Mao Aug. 15, 2024, 7:15 a.m. UTC
If paravirt steal time feature is enabled, there is percpu gpa address
passed from guest vcpu and host modified guest memory space with this gpa
address. When vcpu is reset normally, it will notify host and invalidate
gpa address.

However if VM is crashed and VMM reboots VM forcely, vcpu reboot
notification callback will not be called in VM, host needs invalid the
gpa address, else host will modify guest memory during VM reboots. Here it
is invalidated from vCPU KVM_REG_LOONGARCH_VCPU_RESET ioctl interface.

Also funciton kvm_reset_timer() is removed at vCPU reset stage, since SW
emulated timer is only used in vCPU block state. When vCPU is removed
from block waiting queue, kvm_restore_timer() is called and SW timer
is cancelled. And timer register is cleared at VMM when vCPU is reset.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
---
 arch/loongarch/include/asm/kvm_vcpu.h | 1 -
 arch/loongarch/kvm/timer.c            | 7 -------
 arch/loongarch/kvm/vcpu.c             | 2 +-
 3 files changed, 1 insertion(+), 9 deletions(-)

Comments

Huacai Chen Aug. 26, 2024, 2:49 p.m. UTC | #1
Applied, thanks.

Huacai

On Thu, Aug 15, 2024 at 3:15 PM Bibo Mao <maobibo@loongson.cn> wrote:
>
> If paravirt steal time feature is enabled, there is percpu gpa address
> passed from guest vcpu and host modified guest memory space with this gpa
> address. When vcpu is reset normally, it will notify host and invalidate
> gpa address.
>
> However if VM is crashed and VMM reboots VM forcely, vcpu reboot
> notification callback will not be called in VM, host needs invalid the
> gpa address, else host will modify guest memory during VM reboots. Here it
> is invalidated from vCPU KVM_REG_LOONGARCH_VCPU_RESET ioctl interface.
>
> Also funciton kvm_reset_timer() is removed at vCPU reset stage, since SW
> emulated timer is only used in vCPU block state. When vCPU is removed
> from block waiting queue, kvm_restore_timer() is called and SW timer
> is cancelled. And timer register is cleared at VMM when vCPU is reset.
>
> Signed-off-by: Bibo Mao <maobibo@loongson.cn>
> ---
>  arch/loongarch/include/asm/kvm_vcpu.h | 1 -
>  arch/loongarch/kvm/timer.c            | 7 -------
>  arch/loongarch/kvm/vcpu.c             | 2 +-
>  3 files changed, 1 insertion(+), 9 deletions(-)
>
> diff --git a/arch/loongarch/include/asm/kvm_vcpu.h b/arch/loongarch/include/asm/kvm_vcpu.h
> index c416cb7125c0..86570084e05a 100644
> --- a/arch/loongarch/include/asm/kvm_vcpu.h
> +++ b/arch/loongarch/include/asm/kvm_vcpu.h
> @@ -76,7 +76,6 @@ static inline void kvm_restore_lasx(struct loongarch_fpu *fpu) { }
>  #endif
>
>  void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long hz);
> -void kvm_reset_timer(struct kvm_vcpu *vcpu);
>  void kvm_save_timer(struct kvm_vcpu *vcpu);
>  void kvm_restore_timer(struct kvm_vcpu *vcpu);
>
> diff --git a/arch/loongarch/kvm/timer.c b/arch/loongarch/kvm/timer.c
> index bcc6b6d063d9..74a4b5c272d6 100644
> --- a/arch/loongarch/kvm/timer.c
> +++ b/arch/loongarch/kvm/timer.c
> @@ -188,10 +188,3 @@ void kvm_save_timer(struct kvm_vcpu *vcpu)
>         kvm_save_hw_gcsr(csr, LOONGARCH_CSR_ESTAT);
>         preempt_enable();
>  }
> -
> -void kvm_reset_timer(struct kvm_vcpu *vcpu)
> -{
> -       write_gcsr_timercfg(0);
> -       kvm_write_sw_gcsr(vcpu->arch.csr, LOONGARCH_CSR_TCFG, 0);
> -       hrtimer_cancel(&vcpu->arch.swtimer);
> -}
> diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
> index 16756ffb55e8..6905283f535b 100644
> --- a/arch/loongarch/kvm/vcpu.c
> +++ b/arch/loongarch/kvm/vcpu.c
> @@ -647,7 +647,7 @@ static int kvm_set_one_reg(struct kvm_vcpu *vcpu,
>                                 vcpu->kvm->arch.time_offset = (signed long)(v - drdtime());
>                         break;
>                 case KVM_REG_LOONGARCH_VCPU_RESET:
> -                       kvm_reset_timer(vcpu);
> +                       vcpu->arch.st.guest_addr = 0;
>                         memset(&vcpu->arch.irq_pending, 0, sizeof(vcpu->arch.irq_pending));
>                         memset(&vcpu->arch.irq_clear, 0, sizeof(vcpu->arch.irq_clear));
>                         break;
> --
> 2.39.3
>
diff mbox series

Patch

diff --git a/arch/loongarch/include/asm/kvm_vcpu.h b/arch/loongarch/include/asm/kvm_vcpu.h
index c416cb7125c0..86570084e05a 100644
--- a/arch/loongarch/include/asm/kvm_vcpu.h
+++ b/arch/loongarch/include/asm/kvm_vcpu.h
@@ -76,7 +76,6 @@  static inline void kvm_restore_lasx(struct loongarch_fpu *fpu) { }
 #endif
 
 void kvm_init_timer(struct kvm_vcpu *vcpu, unsigned long hz);
-void kvm_reset_timer(struct kvm_vcpu *vcpu);
 void kvm_save_timer(struct kvm_vcpu *vcpu);
 void kvm_restore_timer(struct kvm_vcpu *vcpu);
 
diff --git a/arch/loongarch/kvm/timer.c b/arch/loongarch/kvm/timer.c
index bcc6b6d063d9..74a4b5c272d6 100644
--- a/arch/loongarch/kvm/timer.c
+++ b/arch/loongarch/kvm/timer.c
@@ -188,10 +188,3 @@  void kvm_save_timer(struct kvm_vcpu *vcpu)
 	kvm_save_hw_gcsr(csr, LOONGARCH_CSR_ESTAT);
 	preempt_enable();
 }
-
-void kvm_reset_timer(struct kvm_vcpu *vcpu)
-{
-	write_gcsr_timercfg(0);
-	kvm_write_sw_gcsr(vcpu->arch.csr, LOONGARCH_CSR_TCFG, 0);
-	hrtimer_cancel(&vcpu->arch.swtimer);
-}
diff --git a/arch/loongarch/kvm/vcpu.c b/arch/loongarch/kvm/vcpu.c
index 16756ffb55e8..6905283f535b 100644
--- a/arch/loongarch/kvm/vcpu.c
+++ b/arch/loongarch/kvm/vcpu.c
@@ -647,7 +647,7 @@  static int kvm_set_one_reg(struct kvm_vcpu *vcpu,
 				vcpu->kvm->arch.time_offset = (signed long)(v - drdtime());
 			break;
 		case KVM_REG_LOONGARCH_VCPU_RESET:
-			kvm_reset_timer(vcpu);
+			vcpu->arch.st.guest_addr = 0;
 			memset(&vcpu->arch.irq_pending, 0, sizeof(vcpu->arch.irq_pending));
 			memset(&vcpu->arch.irq_clear, 0, sizeof(vcpu->arch.irq_clear));
 			break;