From nobody Wed Apr 8 04:39:43 2026 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (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 0D41D3CC9E5 for ; Tue, 10 Mar 2026 23:48:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773186526; cv=none; b=OxF8O5eszdjMq1qCnQ6niqVnc/rUbDrqp0Qr6nnDWq9OSuao17asNptnK3DE5yB6syHqcLKhSQgltn09+8vBJ/ZgMJf7MZO2H/Qk/9vRATOzVt0qLDs/UFzcDr7CSoughEXnHkzYynKQhoiSYMs4yTlVzwf2MC2qqeyYEtQSx3g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773186526; c=relaxed/simple; bh=+CE1sMVEOlVNGNuq/FjIldXhgSK+ycKYDyubuZu6f6M=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=LPwv/bOG3u4hb8UEmkocGRUcQmNNyGZPortQeadpTR2lyoEulm+yYc8kQV73DRcWj/SiVb3VBTh/gI1peFI1rDSP0WTs/c2B/rEkUQGH522L/ry0IaYDrl0xfrEjwfBwDQ1p+g5ds/vvrCUttGiGylMOHOXcmNENXH8fbO8NbtA= 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=MYjlzU+l; arc=none smtp.client-ip=209.85.214.202 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="MYjlzU+l" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-2ae61939fa5so249534845ad.0 for ; Tue, 10 Mar 2026 16:48:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1773186524; x=1773791324; 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=hnqlr1WU2mcNUm5UpgctK6uX9nSxmpmXtaHcxlHX+rw=; b=MYjlzU+l+8u05Vsojp3Ug2veuYeL4oGpNoufcEfdVpM5ookE6kjUpYkFpHbP7uPHwl DBpBIK0jOaYgp+/oinj3vvrlnEwF+twzYZuwkuKtQcIkVAVSWOww7akDdjSkl91wmJJn D2gg02Q2orWZWzQQ1rpAAU3GQ2Id4QETLA2tsA6O2am+9CZKWJ4F5kR5NS5XqiItLMcV ULHSNSnk00SGUKvndU9NWFwzW9movX1Gvk/HGqTThSP2FRCq0X4sEvQ4b5hF+YmlEKFT hZQXUla0JszQo28hbnGOX9TK2VprSSUaXMHA+orxnfUfQBSv2y6d0jd3BHkhiTGzmgwB h+3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773186524; x=1773791324; 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=hnqlr1WU2mcNUm5UpgctK6uX9nSxmpmXtaHcxlHX+rw=; b=pBHdfNQNMcgTuy3kcpTLubHav6w+pacRf/vPYnzlY2Wkw5zIDkpkO66E+c6+xf3w2t gP4nxSjo5DbOowJGlhrFnOO8ri+cdBuZpmfHWLhSuQ5FujzaIDKwSAtcbfqk2m329kBL ZHLU1odysMZW1FZC9wIvU6yXCzrcgIM2BiEoLLNC2TtByDvo1Bb3bqqVtYKG6QRnraE9 5PIM6nrKjCDb/Y6j0kEpwAubvFPg+jKUJEjnh9N/kqphaRITqmWNGqOXUUK0nogVyfZe Aq0P3pPmhp+H37bLYh05MBAVrEuWnSfFqfiwKJ1u9u7DqJAuKUzcdHr0atVc+9Eyn1cN KRyQ== X-Forwarded-Encrypted: i=1; AJvYcCWxq0H1ixMpCx+q+LyWJluPL9JfHvab9nr8US79cag0dVO3X4fUL3TTmHR8FU5I0kPNeTZpRkwH1bFaBpo=@vger.kernel.org X-Gm-Message-State: AOJu0YxMXRHEVPaELfbqC7KRgXFXIF/v+Ep4IxjlY0di2UsTBcr5QgBA EkYBvr3PDvOaLQOgh9aSayFkrjMbsIBnFvY+eDPzE8Z0UuHZVvRZNko0SQn0Gruts0LW/YEwju8 mZ728Hg== X-Received: from pgww3.prod.google.com ([2002:a05:6a02:2c83:b0:c6e:1eff:44ec]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:2349:b0:2ae:7f49:dba6 with SMTP id d9443c01a7336-2aeae7b9c7amr5610675ad.17.1773186524360; Tue, 10 Mar 2026 16:48:44 -0700 (PDT) Reply-To: Sean Christopherson Date: Tue, 10 Mar 2026 16:48:13 -0700 In-Reply-To: <20260310234829.2608037-1-seanjc@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260310234829.2608037-1-seanjc@google.com> X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog Message-ID: <20260310234829.2608037-6-seanjc@google.com> Subject: [PATCH 05/21] KVM: SEV: Lock all vCPUs when synchronzing VMSAs for SNP launch finish From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Jethro Beekman , Alexander Potapenko , "=?UTF-8?q?Carlos=20L=C3=B3pez?=" Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Lock all vCPUs when synchronizing and encrypting VMSAs for SNP guests, as allowing userspace to manipulate and/or run a vCPU while its state is being synchronized would at best corrupt vCPU state, and at worst crash the host kernel. Opportunistically assert that vcpu->mutex is held when synchronizing its VMSA (the SEV-ES path already locks vCPUs). Fixes: ad27ce155566 ("KVM: SEV: Add KVM_SEV_SNP_LAUNCH_FINISH command") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/sev.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 5de36bbc4c53..c10c71608208 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -882,6 +882,8 @@ static int sev_es_sync_vmsa(struct vcpu_svm *svm) u8 *d; int i; =20 + lockdep_assert_held(&vcpu->mutex); + if (vcpu->arch.guest_state_protected) return -EINVAL; =20 @@ -2456,6 +2458,10 @@ static int snp_launch_update_vmsa(struct kvm *kvm, s= truct kvm_sev_cmd *argp) if (kvm_is_vcpu_creation_in_progress(kvm)) return -EBUSY; =20 + ret =3D kvm_lock_all_vcpus(kvm); + if (ret) + return ret; + data.gctx_paddr =3D __psp_pa(sev->snp_context); data.page_type =3D SNP_PAGE_TYPE_VMSA; =20 @@ -2465,12 +2471,12 @@ static int snp_launch_update_vmsa(struct kvm *kvm, = struct kvm_sev_cmd *argp) =20 ret =3D sev_es_sync_vmsa(svm); if (ret) - return ret; + goto err; =20 /* Transition the VMSA page to a firmware state. */ ret =3D rmp_make_private(pfn, INITIAL_VMSA_GPA, PG_LEVEL_4K, sev->asid, = true); if (ret) - return ret; + goto err; =20 /* Issue the SNP command to encrypt the VMSA */ data.address =3D __sme_pa(svm->sev_es.vmsa); @@ -2479,7 +2485,7 @@ static int snp_launch_update_vmsa(struct kvm *kvm, st= ruct kvm_sev_cmd *argp) if (ret) { snp_page_reclaim(kvm, pfn); =20 - return ret; + goto err; } =20 svm->vcpu.arch.guest_state_protected =3D true; @@ -2494,6 +2500,10 @@ static int snp_launch_update_vmsa(struct kvm *kvm, s= truct kvm_sev_cmd *argp) } =20 return 0; + +err: + kvm_unlock_all_vcpus(kvm); + return ret; } =20 static int snp_launch_finish(struct kvm *kvm, struct kvm_sev_cmd *argp) --=20 2.53.0.473.g4a7958ca14-goog