linux-kernel - [PATCH 1/2] KVM: x86: Don't inject PV async #PF if SEND

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Message-ID: <20250215010609.1199982-2-seanjc@google.com>
Date: Fri, 14 Feb 2025 17:06:08 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] KVM: x86: Don't inject PV async #PF if SEND_ALWAYS=0 and
 guest state is protected

Don't inject PV async #PFs into guests with protected register state, i.e.
SEV-ES and SEV-SNP guests, unless the guest has opted-in to receiving #PFs
at CPL0.  For protected guests, the actual CPL of the guest is unknown.

Note, no sane CoCo guest should enable PV async #PF, but the current state
of Linux-as-a-CoCo-guest isn't entirely sane.

Fixes: add5e2f04541 ("KVM: SVM: Add support for the SEV-ES VMSA")
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/x86.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 58b82d6fd77c..3b67425c3e3d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -13395,7 +13395,7 @@ static bool kvm_can_deliver_async_pf(struct kvm_vcpu *vcpu)
 		return false;
 
 	if (vcpu->arch.apf.send_user_only &&
-	    kvm_x86_call(get_cpl)(vcpu) == 0)
+	    (vcpu->arch.guest_state_protected || !kvm_x86_call(get_cpl)(vcpu)))
 		return false;
 
 	if (is_guest_mode(vcpu)) {
-- 
2.48.1.601.g30ceb7b040-goog