From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AF6A933F8DC; Mon, 20 Apr 2026 16:04:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776701069; cv=none; b=LPZgQGqsQLLeNFVuTwN/W5m2eAJVUeuuEYGLMEhp3NP4c1ZimE6ZTGc4ShVNDqF41Ivy3bki/w1as9mPmR6SZPFfhAiBtOs8Crh9OZ9tfBPVoaWwfLNFQlSrAkU13ayT9Foyj882dbj6Z27+SuhYi/61v5O4GW20G4aWN5cbIWw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776701069; c=relaxed/simple; bh=lTB3J1MGtp7wjefclh2cgeN+uBDwCyBQO/kgj90neYI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Oyz86RVvHiRKa82iZVZg7XfeuXIDyPd4XoiofAnYLOIkpEhoyeQKgoYPxwV6RZWiOSEriWdCDExW+xWIXAipoAAWTT9qJ4GYsbxf/oCXGaaJiPjxi8Iy7mLNHMfH+Y8TCfYhjE47/HU401d8SrMduCP6/y4AmPDm2EuRxPg56QE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=tfQLUr8Y; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="tfQLUr8Y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4002BC19425; Mon, 20 Apr 2026 16:04:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776701069; bh=lTB3J1MGtp7wjefclh2cgeN+uBDwCyBQO/kgj90neYI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tfQLUr8YPLrv1fbwJPEFcpzogw+zuOJ5rnwhOUq/2PN2jnUQpNF86/KY6NHJF6bjF jYflQqVw2pORhRFee8kregrmvhK+ZEITEjxd/X/zSi3oL76R0qRNBgivbb5fw//TDv FO0+GfEizJiIYDfkf8HcOw9MpoCJe/dMpZ5CfMwE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sean Christopherson Subject: [PATCH 6.18 169/198] KVM: SEV: Lock all vCPUs when synchronzing VMSAs for SNP launch finish Date: Mon, 20 Apr 2026 17:42:28 +0200 Message-ID: <20260420153941.695647303@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260420153935.605963767@linuxfoundation.org> References: <20260420153935.605963767@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sean Christopherson commit cb923ee6a80f4e604e6242a4702b59251e61a380 upstream. 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 Link: https://patch.msgid.link/20260310234829.2608037-6-seanjc@google.com Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/svm/sev.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -871,6 +871,8 @@ static int sev_es_sync_vmsa(struct vcpu_ u8 *d; int i; + lockdep_assert_held(&vcpu->mutex); + if (vcpu->arch.guest_state_protected) return -EINVAL; @@ -2452,6 +2454,10 @@ static int snp_launch_update_vmsa(struct if (kvm_is_vcpu_creation_in_progress(kvm)) return -EBUSY; + ret = kvm_lock_all_vcpus(kvm); + if (ret) + return ret; + data.gctx_paddr = __psp_pa(sev->snp_context); data.page_type = SNP_PAGE_TYPE_VMSA; @@ -2461,12 +2467,12 @@ static int snp_launch_update_vmsa(struct ret = sev_es_sync_vmsa(svm); if (ret) - return ret; + goto out; /* Transition the VMSA page to a firmware state. */ ret = rmp_make_private(pfn, INITIAL_VMSA_GPA, PG_LEVEL_4K, sev->asid, true); if (ret) - return ret; + goto out; /* Issue the SNP command to encrypt the VMSA */ data.address = __sme_pa(svm->sev_es.vmsa); @@ -2475,7 +2481,7 @@ static int snp_launch_update_vmsa(struct if (ret) { snp_page_reclaim(kvm, pfn); - return ret; + goto out; } svm->vcpu.arch.guest_state_protected = true; @@ -2489,7 +2495,9 @@ static int snp_launch_update_vmsa(struct svm_enable_lbrv(vcpu); } - return 0; +out: + kvm_unlock_all_vcpus(kvm); + return ret; } static int snp_launch_finish(struct kvm *kvm, struct kvm_sev_cmd *argp)