linux-kernel - [RFC PATCH v2 10/17] KVM: SVM: Set VGIF in VMSA area for Secure AVIC guests

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250923050317.205482-11-Neeraj.Upadhyay@amd.com>
Date: Tue, 23 Sep 2025 10:33:10 +0530
From: Neeraj Upadhyay <Neeraj.Upadhyay@....com>
To: <kvm@...r.kernel.org>, <seanjc@...gle.com>, <pbonzini@...hat.com>
CC: <linux-kernel@...r.kernel.org>, <Thomas.Lendacky@....com>,
	<nikunj@....com>, <Santosh.Shukla@....com>, <Vasant.Hegde@....com>,
	<Suravee.Suthikulpanit@....com>, <bp@...en8.de>, <David.Kaplan@....com>,
	<huibo.wang@....com>, <naveen.rao@....com>, <tiala@...rosoft.com>
Subject: [RFC PATCH v2 10/17] KVM: SVM: Set VGIF in VMSA area for Secure AVIC guests

From: Kishon Vijay Abraham I <kvijayab@....com>

Unlike standard SVM which uses the V_GIF (Virtual Global Interrupt Flag)
bit in the VMCB, Secure AVIC ignores this field.

Instead, the hardware requires an equivalent V_GIF bit to be set within
the vintr_ctrl field of the VMSA (Virtual Machine Save Area). Failure
to set this bit will cause the hardware to block all interrupt delivery,
rendering the guest non-functional.

To enable interrupts for Secure AVIC guests, modify sev_es_sync_vmsa()
to unconditionally set the V_GIF_MASK in the VMSA's vintr_ctrl field
whenever Secure AVIC is active. This ensures the hardware correctly
identifies the guest as interruptible.

Signed-off-by: Kishon Vijay Abraham I <kvijayab@....com>
Signed-off-by: Neeraj Upadhyay <Neeraj.Upadhyay@....com>
---
 arch/x86/kvm/svm/sev.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 837ab55a3330..2dee210efb37 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -884,6 +884,9 @@ static int sev_es_sync_vmsa(struct vcpu_svm *svm)

 	save->sev_features = sev->vmsa_features;

+	if (sev_savic_active(vcpu->kvm))
+		save->vintr_ctrl |= V_GIF_MASK;
+
 	/*
 	 * Skip FPU and AVX setup with KVM_SEV_ES_INIT to avoid
 	 * breaking older measurements.
-- 
2.34.1