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 BBB952F1FE3; Mon, 22 Sep 2025 19:44:52 +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=1758570292; cv=none; b=mqJb723g9b3rhU2OfLbT10eUhCw6mjOuRiYcjgizme1yrHgczAKuAIggEdJ4DgKgxqDiZuMCY0xa76n2RrVOo5JCYaX25064Q/3/ENyGqaeJCznSw6mbm94xJbLGag4vl0lxls340fwwV3sWlCVpRHBBEnpJANq6Ev9Rj52xik4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758570292; c=relaxed/simple; bh=GjB5fNxDOjrryCP/HzfJ05rqsndtjbnB/AClmZwHp0g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kYIFhd45BPQLV9C56anBcRlhuJTevOIYZV32bblszaysHjUOxRSMeK/5NFQIxeB2ZSsT8eb8gBR0ktB4CTT442x9XCJXHemOTTBJj6GSuX5Nw3hfovmyTs60TyTCPIwfSH4u6F6EHBV0kfA5J9VtI5y0j7GnFMsADknpqkRBoQQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Gaxn/zXk; 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="Gaxn/zXk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 18A3FC4CEF0; Mon, 22 Sep 2025 19:44:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1758570292; bh=GjB5fNxDOjrryCP/HzfJ05rqsndtjbnB/AClmZwHp0g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Gaxn/zXkJ+XdKUseN+b/6rwa/adHesZytbx0+XgHhQQyNj4Nj8dvnxn2K1AtE6Fka 9Hcn1i2CwZMsi5ON1HY4K89v7m8Ov6ipEqKgWdjDpho+AQhZj2X+hfeHl6kHh+TWmx isJEsMt+XneYRMIxrKXmV1ex3mSaLxZbbhO7BbeA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Tom Lendacky , "Borislav Petkov (AMD)" , stable@kernel.org Subject: [PATCH 6.16 092/149] x86/sev: Guard sev_evict_cache() with CONFIG_AMD_MEM_ENCRYPT Date: Mon, 22 Sep 2025 21:29:52 +0200 Message-ID: <20250922192415.207328819@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250922192412.885919229@linuxfoundation.org> References: <20250922192412.885919229@linuxfoundation.org> User-Agent: quilt/0.68 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 6.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tom Lendacky commit 7f830e126dc357fc086905ce9730140fd4528d66 upstream. The sev_evict_cache() is guest-related code and should be guarded by CONFIG_AMD_MEM_ENCRYPT, not CONFIG_KVM_AMD_SEV. CONFIG_AMD_MEM_ENCRYPT=y is required for a guest to run properly as an SEV-SNP guest, but a guest kernel built with CONFIG_KVM_AMD_SEV=n would get the stub function of sev_evict_cache() instead of the version that performs the actual eviction. Move the function declarations under the appropriate #ifdef. Fixes: 7b306dfa326f ("x86/sev: Evict cache lines during SNP memory validation") Signed-off-by: Tom Lendacky Signed-off-by: Borislav Petkov (AMD) Cc: stable@kernel.org # 6.16.x Link: https://lore.kernel.org/r/70e38f2c4a549063de54052c9f64929705313526.1757708959.git.thomas.lendacky@amd.com Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/sev.h | 38 +++++++++++++++++++------------------- 1 file changed, 19 insertions(+), 19 deletions(-) --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -564,6 +564,24 @@ enum es_result sev_es_ghcb_hv_call(struc extern struct ghcb *boot_ghcb; +static inline void sev_evict_cache(void *va, int npages) +{ + volatile u8 val __always_unused; + u8 *bytes = va; + int page_idx; + + /* + * For SEV guests, a read from the first/last cache-lines of a 4K page + * using the guest key is sufficient to cause a flush of all cache-lines + * associated with that 4K page without incurring all the overhead of a + * full CLFLUSH sequence. + */ + for (page_idx = 0; page_idx < npages; page_idx++) { + val = bytes[page_idx * PAGE_SIZE]; + val = bytes[page_idx * PAGE_SIZE + PAGE_SIZE - 1]; + } +} + #else /* !CONFIG_AMD_MEM_ENCRYPT */ #define snp_vmpl 0 @@ -607,6 +625,7 @@ static inline int snp_send_guest_request static inline int snp_svsm_vtpm_send_command(u8 *buffer) { return -ENODEV; } static inline void __init snp_secure_tsc_prepare(void) { } static inline void __init snp_secure_tsc_init(void) { } +static inline void sev_evict_cache(void *va, int npages) {} #endif /* CONFIG_AMD_MEM_ENCRYPT */ @@ -621,24 +640,6 @@ int rmp_make_shared(u64 pfn, enum pg_lev void snp_leak_pages(u64 pfn, unsigned int npages); void kdump_sev_callback(void); void snp_fixup_e820_tables(void); - -static inline void sev_evict_cache(void *va, int npages) -{ - volatile u8 val __always_unused; - u8 *bytes = va; - int page_idx; - - /* - * For SEV guests, a read from the first/last cache-lines of a 4K page - * using the guest key is sufficient to cause a flush of all cache-lines - * associated with that 4K page without incurring all the overhead of a - * full CLFLUSH sequence. - */ - for (page_idx = 0; page_idx < npages; page_idx++) { - val = bytes[page_idx * PAGE_SIZE]; - val = bytes[page_idx * PAGE_SIZE + PAGE_SIZE - 1]; - } -} #else static inline bool snp_probe_rmptable_info(void) { return false; } static inline int snp_rmptable_init(void) { return -ENOSYS; } @@ -654,7 +655,6 @@ static inline int rmp_make_shared(u64 pf static inline void snp_leak_pages(u64 pfn, unsigned int npages) {} static inline void kdump_sev_callback(void) { } static inline void snp_fixup_e820_tables(void) {} -static inline void sev_evict_cache(void *va, int npages) {} #endif #endif