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 81D5D32ED24; Thu, 16 Jul 2026 13:52:13 +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=1784209934; cv=none; b=amCEUEx5CQLuyGVXVHcN5rwuEo0FSztfpqaEZB6060y3OS6ZW9S8YAxoBargKq+dftU2NyllgcfhJsV7SxZ51TVbQn0HHkCOw8o73HWAB7bDPRyCguU4J46DSwV/GTH90EWrB19yyQT1Lu3XwaRcN+gXvmj6ji5SIEku5Nvbyco= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784209934; c=relaxed/simple; bh=fgXgQVHMPoykghCEJh6I13FqWuJzn1YK0sVGgrpOK/I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iE1zi8QoxLz2cDNIfp/Ein6RcnEE8cUzz4OZEev/rpxjn+CMr3+9YmZB1eJ7AdHWNbM4gYG+nOddHCtQCpnZeyIh6/TLMQscazy/eKiTPoN0ZESsltq959q6Ez+dOBxHi4cZ8+djzJsxlBepeVCYdYkKXZCCifRFnvS5ZssOttA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=jW2ayp5K; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="jW2ayp5K" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E751B1F00A3A; Thu, 16 Jul 2026 13:52:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784209933; bh=sY7rOb4sbTX7NODegDkodLoxcckHN0HSE7rqu/gzYH0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=jW2ayp5KQcOlBCziRVCuJz08VbivDyCviXfpblRzG1cVuqyDDqe17doQIF8NYdLKa 95cX4beex3bDLoFEPI+ySItxMrQhdMvEf19r9PRAW7KcaKQptDjQefF/uygf9ktQxH wpNX81i+YPL9fPRfazDEPgL5AX47xRJUD2dB+yms= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Tycho Andersen (AMD)" , Tom Lendacky , Herbert Xu Subject: [PATCH 7.1 374/518] crypto: ccp - Do not initialize SNP for ioctl(SNP_CONFIG) Date: Thu, 16 Jul 2026 15:30:42 +0200 Message-ID: <20260716133056.011888129@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260716133047.772246337@linuxfoundation.org> References: <20260716133047.772246337@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 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tycho Andersen (AMD) commit 08f0e65e784c4b20e6e620dd4f68d8636073a3d2 upstream. 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: Greg Kroah-Hartman --- drivers/crypto/ccp/sev-dev.c | 33 ++++----------------------------- 1 file changed, 4 insertions(+), 29 deletions(-) --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -1727,21 +1727,6 @@ static int sev_move_to_init_state(struct 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, 0); - 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; @@ -2451,8 +2436,6 @@ static int sev_ioctl_do_snp_set_config(s { 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; @@ -2460,21 +2443,13 @@ static int sev_ioctl_do_snp_set_config(s 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)