From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 45DF543D518 for ; Mon, 20 Jul 2026 17:15:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784567746; cv=none; b=ccF1gjh0Uf35gQDanRYksJXkRFWIWmrOKcMx5s4ktdg4sVKcaBubXML0JmFV7nIh7oDGnBXISa942xfQXop5H6ejsqm8UfgErWR+wVnARRdmEy42WEJFG8Ra+wBP+l2jOQpiF8W6SdH+tl/5VtX0JsuwoqkUMEy6rcOPOKsUDuw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784567746; c=relaxed/simple; bh=eCbzxpEeV0HHh/mMaxPxKBYRx+SVdvYt2l06wPwlxkI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Wz+ksfCbwjgoRB6/cxg+dUZ9BQ2zYFinid0bY4hZjokuqGYKDmRVNU+069SyHtsgGRCNrydCXw3hENc8e+WSQPvWnHNrcMjGvPYhcPBWCybI/5SZsRA2bU+OxzYr1Vse/eWQN1FXL1oEKeQ92eYOl1Wgp5GAAnopQ9/IPg2wnDo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OEVUsadJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OEVUsadJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A08DE1F01579; Mon, 20 Jul 2026 17:15:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784567742; bh=/u3hSE/5Z4e/KWi/OdzYrtZkqzDsQDdoxL54XMhwxwo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=OEVUsadJgDwNwJth2ie0Yu3kZXd4/MXv2voGg1wrUS2w+7RXYjfeodR4xcwRKjW1F B/4P/aGLNy0Az3VPfDFe2pGhzmufC+5uvwHWKEQYV+hgL3gwZ3VNT51UHnIDrUu4fb qni45fZvzh6emtxeI3J0qIxtfUMuIdzGG/FNRVEGTBeetumlTBpgX5t/7zryyd3ZQD BmewoGaS7hzYSLY4EZklzmYHpHveK/us9pY/M+G1OsB5EwaZlZX6CP1y3Vg7MUQx0M FPsTDnBNpN2w9RyyLBHc7tXpACkYSise5kCOl0vFudMk6T8VkAT6EyyuhaYPjGCAqL XY/j4rYCA+8fg== From: Sasha Levin To: stable@vger.kernel.org Cc: "Tycho Andersen (AMD)" , Tom Lendacky , Herbert Xu , Sasha Levin Subject: [PATCH 6.12.y 6/6] crypto: ccp - Do not initialize SNP for ioctl(SNP_CONFIG) Date: Mon, 20 Jul 2026 13:15:35 -0400 Message-ID: <20260720171535.2695659-6-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260720171535.2695659-1-sashal@kernel.org> References: <2026071538-unmapped-affiliate-9ff5@gregkh> <20260720171535.2695659-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: "Tycho Andersen (AMD)" [ Upstream commit 08f0e65e784c4b20e6e620dd4f68d8636073a3d2 ] Sashiko notes: > if SEV initialization fails and KVM is actively running normal VMs, could a > userspace process trigger this code path via /dev/sev ioctls (e.g., > SEV_PDH_GEN) and zero out MSR_VM_HSAVE_PA globally? Would the next VMRUN > execution for an active VM trigger a general protection fault and crash the > host? Refuse to re-try initialization if SNP is not already initialized for SNP_CONFIG. This is technically an ABI break: before if SNP initialization failed it could be transparently retriggered by this ioctl, and if no VMs were running, everything worked fine. Hopefully this is enough of a corner case that nobody will notice, but someone does, there are a few options: * do something like symbol_get() for kvm and refuse to initialize if KVM is loaded * check each cpu's HSAVE_PA for non-zero data before re-initializing * once initialization has failed, continue to refuse to initialize until the ccp module is unloaded Fixes: ceac7fb89e8d ("crypto: ccp - Ensure implicit SEV/SNP init and shutdown in ioctls") Reported-by: Sashiko Assisted-by: Gemini:gemini-3.1-pro-preview Link: https://sashiko.dev/#/patchset/20260324161301.1353976-1-tycho%40kernel.org CC: Signed-off-by: Tycho Andersen (AMD) Reviewed-by: Tom Lendacky Signed-off-by: Herbert Xu Signed-off-by: Sasha Levin --- drivers/crypto/ccp/sev-dev.c | 33 ++++----------------------------- 1 file changed, 4 insertions(+), 29 deletions(-) diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c index c1e003cae057a2..6387baca7b553a 100644 --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -1433,21 +1433,6 @@ static int sev_move_to_init_state(struct sev_issue_cmd *argp, bool *shutdown_req return 0; } -static int snp_move_to_init_state(struct sev_issue_cmd *argp, bool *shutdown_required) -{ - int error, rc; - - rc = __sev_snp_init_locked(&error); - if (rc) { - argp->error = SEV_RET_INVALID_PLATFORM_STATE; - return rc; - } - - *shutdown_required = true; - - return 0; -} - static int sev_ioctl_do_reset(struct sev_issue_cmd *argp, bool writable) { int state, rc; @@ -2141,8 +2126,6 @@ static int sev_ioctl_do_snp_set_config(struct sev_issue_cmd *argp, bool writable { struct sev_device *sev = psp_master->sev_data; struct sev_user_data_snp_config config; - bool shutdown_required = false; - int ret, error; if (!argp->data) return -EINVAL; @@ -2150,21 +2133,13 @@ static int sev_ioctl_do_snp_set_config(struct sev_issue_cmd *argp, bool writable if (!writable) return -EPERM; + if (!sev->snp_initialized) + return -ENODEV; + if (copy_from_user(&config, (void __user *)argp->data, sizeof(config))) return -EFAULT; - if (!sev->snp_initialized) { - ret = snp_move_to_init_state(argp, &shutdown_required); - if (ret) - return ret; - } - - ret = __sev_do_cmd_locked(SEV_CMD_SNP_CONFIG, &config, &argp->error); - - if (shutdown_required) - __sev_snp_shutdown_locked(&error, false); - - return ret; + return __sev_do_cmd_locked(SEV_CMD_SNP_CONFIG, &config, &argp->error); } static int sev_ioctl_do_snp_vlek_load(struct sev_issue_cmd *argp, bool writable) -- 2.53.0