diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/boot/compressed/head_64.S | 37 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/mem_encrypt.S | 36 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/misc.h | 4 | ||||
| -rw-r--r-- | arch/x86/boot/compressed/sev.c | 36 |
4 files changed, 60 insertions, 53 deletions
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index dea95301196b..4cd661165d4a 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -189,11 +189,11 @@ SYM_FUNC_START(startup_32) subl $32, %eax /* Encryption bit is always above bit 31 */ bts %eax, %edx /* Set encryption mask for page tables */ /* - * Mark SEV as active in sev_status so that startup32_check_sev_cbit() - * will do a check. The sev_status memory will be fully initialized - * with the contents of MSR_AMD_SEV_STATUS later in - * set_sev_encryption_mask(). For now it is sufficient to know that SEV - * is active. + * Set MSR_AMD64_SEV_ENABLED_BIT in sev_status so that + * startup32_check_sev_cbit() will do a check. sev_enable() will + * initialize sev_status with all the bits reported by + * MSR_AMD_SEV_STATUS later, but only MSR_AMD64_SEV_ENABLED_BIT + * needs to be set for now. */ movl $1, rva(sev_status)(%ebp) 1: @@ -447,6 +447,23 @@ SYM_CODE_START(startup_64) call load_stage1_idt popq %rsi +#ifdef CONFIG_AMD_MEM_ENCRYPT + /* + * Now that the stage1 interrupt handlers are set up, #VC exceptions from + * CPUID instructions can be properly handled for SEV-ES guests. + * + * For SEV-SNP, the CPUID table also needs to be set up in advance of any + * CPUID instructions being issued, so go ahead and do that now via + * sev_enable(), which will also handle the rest of the SEV-related + * detection/setup to ensure that has been done in advance of any dependent + * code. + */ + pushq %rsi + movq %rsi, %rdi /* real mode address */ + call sev_enable + popq %rsi +#endif + /* * paging_prepare() sets up the trampoline and checks if we need to * enable 5-level paging. @@ -558,17 +575,7 @@ SYM_FUNC_START_LOCAL_NOALIGN(.Lrelocated) shrq $3, %rcx rep stosq -/* - * If running as an SEV guest, the encryption mask is required in the - * page-table setup code below. When the guest also has SEV-ES enabled - * set_sev_encryption_mask() will cause #VC exceptions, but the stage2 - * handler can't map its GHCB because the page-table is not set up yet. - * So set up the encryption mask here while still on the stage1 #VC - * handler. Then load stage2 IDT and switch to the kernel's own - * page-table. - */ pushq %rsi - call set_sev_encryption_mask call load_stage2_idt /* Pass boot_params to initialize_identity_maps() */ diff --git a/arch/x86/boot/compressed/mem_encrypt.S b/arch/x86/boot/compressed/mem_encrypt.S index a63424d13627..a73e4d783cae 100644 --- a/arch/x86/boot/compressed/mem_encrypt.S +++ b/arch/x86/boot/compressed/mem_encrypt.S @@ -187,42 +187,6 @@ SYM_CODE_END(startup32_vc_handler) .code64 #include "../../kernel/sev_verify_cbit.S" -SYM_FUNC_START(set_sev_encryption_mask) -#ifdef CONFIG_AMD_MEM_ENCRYPT - push %rbp - push %rdx - - movq %rsp, %rbp /* Save current stack pointer */ - - call get_sev_encryption_bit /* Get the encryption bit position */ - testl %eax, %eax - jz .Lno_sev_mask - - bts %rax, sme_me_mask(%rip) /* Create the encryption mask */ - - /* - * Read MSR_AMD64_SEV again and store it to sev_status. Can't do this in - * get_sev_encryption_bit() because this function is 32-bit code and - * shared between 64-bit and 32-bit boot path. - */ - movl $MSR_AMD64_SEV, %ecx /* Read the SEV MSR */ - rdmsr - - /* Store MSR value in sev_status */ - shlq $32, %rdx - orq %rdx, %rax - movq %rax, sev_status(%rip) - -.Lno_sev_mask: - movq %rbp, %rsp /* Restore original stack pointer */ - - pop %rdx - pop %rbp -#endif - - xor %rax, %rax - RET -SYM_FUNC_END(set_sev_encryption_mask) .data diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index 16ed360b6692..23e0e395084a 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -120,12 +120,12 @@ static inline void console_init(void) { } #endif -void set_sev_encryption_mask(void); - #ifdef CONFIG_AMD_MEM_ENCRYPT +void sev_enable(struct boot_params *bp); void sev_es_shutdown_ghcb(void); extern bool sev_es_check_ghcb_fault(unsigned long address); #else +static inline void sev_enable(struct boot_params *bp) { } static inline void sev_es_shutdown_ghcb(void) { } static inline bool sev_es_check_ghcb_fault(unsigned long address) { diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c index 4e82101b7d13..27ccd5a5ff60 100644 --- a/arch/x86/boot/compressed/sev.c +++ b/arch/x86/boot/compressed/sev.c @@ -201,3 +201,39 @@ finish: else if (result != ES_RETRY) sev_es_terminate(GHCB_SEV_ES_GEN_REQ); } + +void sev_enable(struct boot_params *bp) +{ + unsigned int eax, ebx, ecx, edx; + struct msr m; + + /* Check for the SME/SEV support leaf */ + eax = 0x80000000; + ecx = 0; + native_cpuid(&eax, &ebx, &ecx, &edx); + if (eax < 0x8000001f) + return; + + /* + * Check for the SME/SEV feature: + * CPUID Fn8000_001F[EAX] + * - Bit 0 - Secure Memory Encryption support + * - Bit 1 - Secure Encrypted Virtualization support + * CPUID Fn8000_001F[EBX] + * - Bits 5:0 - Pagetable bit position used to indicate encryption + */ + eax = 0x8000001f; + ecx = 0; + native_cpuid(&eax, &ebx, &ecx, &edx); + /* Check whether SEV is supported */ + if (!(eax & BIT(1))) + return; + + /* Set the SME mask if this is an SEV guest. */ + boot_rdmsr(MSR_AMD64_SEV, &m); + sev_status = m.q; + if (!(sev_status & MSR_AMD64_SEV_ENABLED)) + return; + + sme_me_mask = BIT_ULL(ebx & 0x3f); +} |