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 F07103D3331; Tue, 24 Mar 2026 16:13:24 +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=1774368805; cv=none; b=RDxW23E81X+6M6cZRwc4HMw+umgM+gXmUJsezO8NY0eEtFURM2T/8jbqRy90t0veHjY+uxiyKN0xttqKK84NyIRE6Q5uuqionEvz8RTPWWQ9iufsnq+c9dq5ftFsFSahgOIfwaNG7GC/6LqcJ8/GsLLIBboIUZyhz8kHKxYAiXw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774368805; c=relaxed/simple; bh=C0cxEGO7pt7MEvBETiZvMxPEovrTI69gUhimZn73XMs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=X2STEepMkR0w/P3Q6uuF8kNVJiyUdcEnGD7aem74/xOP5BjK/ZXkYL+Ek3r+r5dNCqGTxvAzyzVhKcVqI8yr+5rHLFOqc3ybvWTcpQqdJ8TYkuPU+w97xcVwvHgQMGs6BwKpuQPXLiEOdym4whqePk3EEWCzP1l7wJX2irJSeYE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jLCTnQNJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jLCTnQNJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 91264C19424; Tue, 24 Mar 2026 16:13:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774368804; bh=C0cxEGO7pt7MEvBETiZvMxPEovrTI69gUhimZn73XMs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jLCTnQNJPBAOJef4dOdpbbAypmUrud21smWgI0hNoIDyefBNT5v7dR3zfaja5pnGH TIUOlBuA28OFL1qsZn4dqbTVAIb7yFWZ1I489GB28wA7bkZkKJeFQ9uHQ0MhceOdDH UufiSxoP3omqtw4BX1JNRM+kf90dvrGWbHqigJZmtRlanwpmTVysVrXqr79bTPAcbw X7lJqmGMRGUoqCsBb+S887nHNN3JD//2/YNRshwUdsa6MKbr4kZKYvsiVERgasjs1s B37LEe0Zgk/AlKZeEv90Miu52b/8FJ0u804ADGKAbgq+Gz/vgqbXhiOxSFlLl6hrh3 MqyjyMFHRzxYA== From: Tycho Andersen To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Ashish Kalra , Tom Lendacky , John Allen , Herbert Xu , "David S. Miller" , Ard Biesheuvel , Neeraj Upadhyay , Kishon Vijay Abraham I , Alexey Kardashevskiy , Nikunj A Dadhania , "Peter Zijlstra (Intel)" , Kim Phillips , Sean Christopherson Cc: linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, "Tycho Andersen (AMD)" Subject: [PATCH v4 2/7] x86/sev: Create snp_prepare() Date: Tue, 24 Mar 2026 10:12:56 -0600 Message-ID: <20260324161301.1353976-3-tycho@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260324161301.1353976-1-tycho@kernel.org> References: <20260324161301.1353976-1-tycho@kernel.org> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: "Tycho Andersen (AMD)" In preparation for delayed SNP initialization, create a function snp_prepare() that does the necessary architecture setup. Export this function for the ccp module to allow it to do the setup as necessary. Also move {mfd,snp}_enable out of the __init section, since these will be called later. Signed-off-by: Tycho Andersen (AMD) Reviewed-by: Tom Lendacky --- arch/x86/include/asm/sev.h | 2 ++ arch/x86/virt/svm/sev.c | 46 ++++++++++++++++++++++---------------- 2 files changed, 29 insertions(+), 19 deletions(-) diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index 0e6c0940100f..2140e26dec6c 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -661,6 +661,7 @@ static inline void snp_leak_pages(u64 pfn, unsigned int pages) { __snp_leak_pages(pfn, pages, true); } +void snp_prepare(void); #else static inline bool snp_probe_rmptable_info(void) { return false; } static inline int snp_rmptable_init(void) { return -ENOSYS; } @@ -677,6 +678,7 @@ static inline void __snp_leak_pages(u64 pfn, unsigned int npages, bool dump_rmp) 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 snp_prepare(void) {} #endif #endif diff --git a/arch/x86/virt/svm/sev.c b/arch/x86/virt/svm/sev.c index 025606969823..6f4c3f6e2082 100644 --- a/arch/x86/virt/svm/sev.c +++ b/arch/x86/virt/svm/sev.c @@ -132,7 +132,7 @@ static unsigned long snp_nr_leaked_pages; #undef pr_fmt #define pr_fmt(fmt) "SEV-SNP: " fmt -static __init void mfd_enable(void *arg) +static void mfd_enable(void *arg) { if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP)) return; @@ -140,7 +140,7 @@ static __init void mfd_enable(void *arg) msr_set_bit(MSR_AMD64_SYSCFG, MSR_AMD64_SYSCFG_MFDM_BIT); } -static __init void snp_enable(void *arg) +static void snp_enable(void *arg) { u64 val; @@ -503,6 +503,30 @@ static bool __init setup_rmptable(void) return true; } +void snp_prepare(void) +{ + u64 val; + + /* + * Check if SEV-SNP is already enabled, this can happen in case of + * kexec boot. + */ + rdmsrq(MSR_AMD64_SYSCFG, val); + if (val & MSR_AMD64_SYSCFG_SNP_EN) + return; + + clear_rmp(); + + /* + * MtrrFixDramModEn is not shared between threads on a core, + * therefore it must be set on all CPUs prior to enabling SNP. + */ + on_each_cpu(mfd_enable, NULL, 1); + + on_each_cpu(snp_enable, NULL, 1); +} +EXPORT_SYMBOL_FOR_MODULES(snp_prepare, "ccp"); + /* * Do the necessary preparations which are verified by the firmware as * described in the SNP_INIT_EX firmware command description in the SNP @@ -510,8 +534,6 @@ static bool __init setup_rmptable(void) */ int __init snp_rmptable_init(void) { - u64 val; - if (WARN_ON_ONCE(!cc_platform_has(CC_ATTR_HOST_SEV_SNP))) return -ENOSYS; @@ -521,22 +543,8 @@ int __init snp_rmptable_init(void) if (!setup_rmptable()) return -ENOSYS; - /* - * Check if SEV-SNP is already enabled, this can happen in case of - * kexec boot. - */ - rdmsrq(MSR_AMD64_SYSCFG, val); - if (val & MSR_AMD64_SYSCFG_SNP_EN) - goto skip_enable; - - clear_rmp(); - - /* MtrrFixDramModEn must be enabled on all the CPUs prior to enabling SNP. */ - on_each_cpu(mfd_enable, NULL, 1); - - on_each_cpu(snp_enable, NULL, 1); + snp_prepare(); -skip_enable: /* * Setting crash_kexec_post_notifiers to 'true' to ensure that SNP panic * notifier is invoked to do SNP IOMMU shutdown before kdump. -- 2.53.0