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..ccec52952573 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 +503,33 @@ 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(); + + cpus_read_lock(); + + /* + * 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); + + cpus_read_unlock(); +} +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 +537,6 @@ 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 +546,8 @@ 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; + snp_prepare(); - 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); - -skip_enable: /* * Setting crash_kexec_post_notifiers to 'true' to ensure that SNP panic * notifier is invoked to do SNP IOMMU shutdown before kdump.