From nobody Sat Feb 7 09:10:50 2026 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B39602D0274 for ; Tue, 10 Jun 2025 22:58:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749596288; cv=none; b=VqpcZTsv6vDnxuz29yvFjdKpgnsxawxphbon6yue8upBJPmVSQcCwTvwVcRLY72iGMCbR5lSY+5K0ZJOkar5s4p5BY8AET8qpol2v/4+7uFDdgnob5pmk33WfERSlb8C6cWtscv+GX5/d+9Bvs8vOxYipWLSEPMH0VjRSOZkxI0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749596288; c=relaxed/simple; bh=WyvxrUW0cLAtlzKfHBSk04hVbpED9wnvZwlJrQHf/jo=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=FCqEyfF6jUQWjIAymLhnK9Pk3nH0eiF5+vgDFNrD08bRFz0vQn//9W75hCnPwb583sB+VjfQU6k3M+ARsae5thkmEfE7oWErAsSMmdCW3igEsGk7nQvPOeqa1dERy9EaiFrWm+FuIFtO52OS+iHxErseX2otCeXLCQSV1iLBOt0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=JWtDkqpT; arc=none smtp.client-ip=209.85.210.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="JWtDkqpT" Received: by mail-pf1-f201.google.com with SMTP id d2e1a72fcca58-748475d2a79so2372960b3a.3 for ; Tue, 10 Jun 2025 15:58:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1749596286; x=1750201086; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=L9AHHsZZFEY3JtnvHOf80Exk/6rqnszTyKb98S72dSw=; b=JWtDkqpTBJ7JHMLoYxdQ1/V6kAWOwHFRb/svV81P+2hiUteFa+7/yMOz2j1EtsN4F+ PMwKw0JlQtXbrt6QXCO/5hdpZ4s8DPHUa74W5U+sacv/jVloefz5EPWIZ74iREOxJh2t d2Y6DigKXMa9I/6yhrYzkyZmDwhd3J3/vVkzTUEYS/Fx6hfSgO8AqhHrCrDsNpYa/Ib3 4V3CCSJaQRQKky2DfylObE6z6rMB2UcvstfF4mbzpTarxzovYAWzrRZp1bqLNvhfTJ1W FddYz7WaBAu81XoYLGBBWfwIccZZSqUmHwqRYMWkN9X5djym+duREDuRAOkBKlZ6LrQa nw8w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1749596286; x=1750201086; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=L9AHHsZZFEY3JtnvHOf80Exk/6rqnszTyKb98S72dSw=; b=p1m5fjrx1UyzQh9udY8/mNTvQIGAuQBITy7PkHpJAcGmWjS/sZWzPvB/tADAMogULy ketxoGu6yJlrakBDiRtIHLwhogvTgU/HHPqNCWJbEYxWD1RiQ+gHmuS8IET+ofEwf8gO 3EZ11sMsJvFlmW3TTJrHyWCTF8L7vYmaezHhP/hC7Nx8WKt0s7K+IjQZKeSlWr+xRKUk MV+w3JP4NZ9MDUK3yi2BlVx6bTGlWs2KL7Xg56izmXisyM1ZhRlUQWDCKLw13B1lcyv7 5mF248jC9o5fMPg70+4KAlL3PidhjGUwaTZ1X/PQbj59fLIKL1CTWNRxgegEOnRj+k8E YRzA== X-Forwarded-Encrypted: i=1; AJvYcCU6xWz+su/Z0ZiQspT17dqL9BAkhXYIrLJVu3t9aDJHBjBqbrD0sAlF6fv9kiXjf0lK+vC4ky9iWDAuQvw=@vger.kernel.org X-Gm-Message-State: AOJu0Yxp9x2fEajrNDNh0n1qNlhq2xf3TncS91HXr/jTzABdbXzJFcNR 83JL8oNEVl/J1VnmdvaTVoLkFB+x6Zox17gCZe7hb/tomxqouJFygf5QooPy3TyYzlg0YUmXaJn svxbVPg== X-Google-Smtp-Source: AGHT+IFia0HrIGKRFAOQayknYEgvlxifUBSRoYzh/E4Z5DYAi7waoDf+mrtMSWocIZN2sN92+TeC14KpajU= X-Received: from pfbgq46.prod.google.com ([2002:a05:6a00:3bee:b0:747:af58:72ca]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:124c:b0:742:da7c:3f30 with SMTP id d2e1a72fcca58-7486ce2a03fmr1763834b3a.19.1749596286001; Tue, 10 Jun 2025 15:58:06 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 10 Jun 2025 15:57:20 -0700 In-Reply-To: <20250610225737.156318-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250610225737.156318-1-seanjc@google.com> X-Mailer: git-send-email 2.50.0.rc0.642.g800a2b2222-goog Message-ID: <20250610225737.156318-16-seanjc@google.com> Subject: [PATCH v2 15/32] KVM: SVM: Pass through GHCB MSR if and only if VM is an SEV-ES guest From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Chao Gao , Borislav Petkov , Xin Li , Dapeng Mi , Francesco Lavra , Manali Shukla Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Disable interception of the GHCB MSR if and only if the VM is an SEV-ES guest. While the exact behavior is completely undocumented in the APM, common sense and testing on SEV-ES capable CPUs says that accesses to the GHCB from non-SEV-ES guests will #GP. I.e. from the guest's perspective, no functional change intended. Fixes: 376c6d285017 ("KVM: SVM: Provide support for SEV-ES vCPU creation/lo= ading") Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/sev.c | 3 ++- arch/x86/kvm/svm/svm.c | 2 +- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 74dab69fb69e..a020aa755a7e 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -4448,7 +4448,8 @@ static void sev_es_init_vmcb(struct vcpu_svm *svm) /* Can't intercept XSETBV, HV can't modify XCR0 directly */ svm_clr_intercept(svm, INTERCEPT_XSETBV); =20 - /* Clear intercepts on selected MSRs */ + /* Clear intercepts on MSRs that are context switched by hardware. */ + svm_disable_intercept_for_msr(vcpu, MSR_AMD64_SEV_ES_GHCB, MSR_TYPE_RW); svm_disable_intercept_for_msr(vcpu, MSR_EFER, MSR_TYPE_RW); svm_disable_intercept_for_msr(vcpu, MSR_IA32_CR_PAT, MSR_TYPE_RW); } diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 93d66109f495..7747f9bc3e9d 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -110,7 +110,7 @@ static const struct svm_direct_access_msrs { { .index =3D MSR_IA32_XSS, .always =3D false }, { .index =3D MSR_EFER, .always =3D false }, { .index =3D MSR_IA32_CR_PAT, .always =3D false }, - { .index =3D MSR_AMD64_SEV_ES_GHCB, .always =3D true }, + { .index =3D MSR_AMD64_SEV_ES_GHCB, .always =3D false }, { .index =3D MSR_TSC_AUX, .always =3D false }, { .index =3D X2APIC_MSR(APIC_ID), .always =3D false }, { .index =3D X2APIC_MSR(APIC_LVR), .always =3D false }, --=20 2.50.0.rc0.642.g800a2b2222-goog