> On 3 Sep 2019, at 17:29, Alexander Graf <g...@amazon.com> wrote:
> 
> We can easily route hardware interrupts directly into VM context when
> they target the "Fixed" or "LowPriority" delivery modes.
> 
> However, on modes such as "SMI" or "Init", we need to go via KVM code
> to actually put the vCPU into a different mode of operation, so we can
> not post the interrupt
> 
> Add code in the SVM PI logic to explicitly refuse to establish posted
> mappings for advanced IRQ deliver modes.
> 
> This fixes a bug I have with code which configures real hardware to
> inject virtual SMIs into my guest.
> 
> Signed-off-by: Alexander Graf <g...@amazon.com>

Nit: I prefer to squash both commits into one that change both VMX & SVM.
As it’s exactly the same change.

> ---
> arch/x86/kvm/svm.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
> 
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 1f220a85514f..9a6ea78c3239 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -5266,6 +5266,21 @@ get_pi_vcpu_info(struct kvm *kvm, struct 
> kvm_kernel_irq_routing_entry *e,
>               return -1;
>       }
> 
> +     switch (irq.delivery_mode) {
> +     case dest_Fixed:
> +     case dest_LowestPrio:
> +             break;
> +     default:
> +             /*
> +              * For non-trivial interrupt events, we need to go
> +              * through the full KVM IRQ code, so refuse to take
> +              * any direct PI assignments here.
> +              */
> +             pr_debug("SVM: %s: use legacy intr remap mode for irq %u\n",
> +                      __func__, irq.vector);
> +             return -1;
> +     }
> +

Prefer changing printed string to something different than the 
!kvm_intr_is_single_vcpu() case.
To assist debugging.

Having said that,
Reviewed-by: Liran Alon <liran.a...@oracle.com>

-Liran

>       pr_debug("SVM: %s: use GA mode for irq %u\n", __func__,
>                irq.vector);
>       *svm = to_svm(vcpu);
> @@ -5314,6 +5329,7 @@ static int svm_update_pi_irte(struct kvm *kvm, unsigned 
> int host_irq,
>                * 1. When cannot target interrupt to a specific vcpu.
>                * 2. Unsetting posted interrupt.
>                * 3. APIC virtialization is disabled for the vcpu.
> +              * 4. IRQ has extended delivery mode (SMI, INIT, etc)
>                */
>               if (!get_pi_vcpu_info(kvm, e, &vcpu_info, &svm) && set &&
>                   kvm_vcpu_apicv_active(&svm->vcpu)) {
> -- 
> 2.17.1
> 
> 
> 
> 
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