diff options
Diffstat (limited to 'arch/x86/boot/compressed/sev.c')
| -rw-r--r-- | arch/x86/boot/compressed/sev.c | 266 |
1 files changed, 157 insertions, 109 deletions
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c index ec71846d28c9..bb55934c1cee 100644 --- a/arch/x86/boot/compressed/sev.c +++ b/arch/x86/boot/compressed/sev.c @@ -127,7 +127,35 @@ static bool fault_in_kernel_space(unsigned long address) #include "../../lib/insn.c" /* Include code for early handlers */ -#include "../../kernel/sev-shared.c" +#include "../../coco/sev/shared.c" + +static struct svsm_ca *svsm_get_caa(void) +{ + return boot_svsm_caa; +} + +static u64 svsm_get_caa_pa(void) +{ + return boot_svsm_caa_pa; +} + +static int svsm_perform_call_protocol(struct svsm_call *call) +{ + struct ghcb *ghcb; + int ret; + + if (boot_ghcb) + ghcb = boot_ghcb; + else + ghcb = NULL; + + do { + ret = ghcb ? svsm_perform_ghcb_protocol(ghcb, call) + : svsm_perform_msr_protocol(call); + } while (ret == -EAGAIN); + + return ret; +} bool sev_snp_enabled(void) { @@ -145,8 +173,8 @@ static void __page_state_change(unsigned long paddr, enum psc_op op) * If private -> shared then invalidate the page before requesting the * state change in the RMP table. */ - if (op == SNP_PAGE_STATE_SHARED && pvalidate(paddr, RMP_PG_SIZE_4K, 0)) - sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE); + if (op == SNP_PAGE_STATE_SHARED) + pvalidate_4k_page(paddr, paddr, false); /* Issue VMGEXIT to change the page state in RMP table. */ sev_es_wr_ghcb_msr(GHCB_MSR_PSC_REQ_GFN(paddr >> PAGE_SHIFT, op)); @@ -161,8 +189,8 @@ static void __page_state_change(unsigned long paddr, enum psc_op op) * Now that page state is changed in the RMP table, validate it so that it is * consistent with the RMP entry. */ - if (op == SNP_PAGE_STATE_PRIVATE && pvalidate(paddr, RMP_PG_SIZE_4K, 1)) - sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE); + if (op == SNP_PAGE_STATE_PRIVATE) + pvalidate_4k_page(paddr, paddr, true); } void snp_set_page_private(unsigned long paddr) @@ -256,6 +284,16 @@ void sev_es_shutdown_ghcb(void) error("SEV-ES CPU Features missing."); /* + * This denotes whether to use the GHCB MSR protocol or the GHCB + * shared page to perform a GHCB request. Since the GHCB page is + * being changed to encrypted, it can't be used to perform GHCB + * requests. Clear the boot_ghcb variable so that the GHCB MSR + * protocol is used to change the GHCB page over to an encrypted + * page. + */ + boot_ghcb = NULL; + + /* * GHCB Page must be flushed from the cache and mapped encrypted again. * Otherwise the running kernel will see strange cache effects when * trying to use that page. @@ -335,26 +373,6 @@ finish: sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ); } -static void enforce_vmpl0(void) -{ - u64 attrs; - int err; - - /* - * RMPADJUST modifies RMP permissions of a lesser-privileged (numerically - * higher) privilege level. Here, clear the VMPL1 permission mask of the - * GHCB page. If the guest is not running at VMPL0, this will fail. - * - * If the guest is running at VMPL0, it will succeed. Even if that operation - * modifies permission bits, it is still ok to do so currently because Linux - * SNP guests are supported only on VMPL0 so VMPL1 or higher permission masks - * changing is a don't-care. - */ - attrs = 1; - if (rmpadjust((unsigned long)&boot_ghcb_page, RMP_PG_SIZE_4K, attrs)) - sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0); -} - /* * SNP_FEATURES_IMPL_REQ is the mask of SNP features that will need * guest side implementation for proper functioning of the guest. If any @@ -383,7 +401,8 @@ static void enforce_vmpl0(void) * by the guest kernel. As and when a new feature is implemented in the * guest kernel, a corresponding bit should be added to the mask. */ -#define SNP_FEATURES_PRESENT MSR_AMD64_SNP_DEBUG_SWAP +#define SNP_FEATURES_PRESENT (MSR_AMD64_SNP_DEBUG_SWAP | \ + MSR_AMD64_SNP_SECURE_TSC) u64 snp_get_unsupported_features(u64 status) { @@ -413,6 +432,92 @@ void snp_check_features(void) } } +/* Search for Confidential Computing blob in the EFI config table. */ +static struct cc_blob_sev_info *find_cc_blob_efi(struct boot_params *bp) +{ + unsigned long cfg_table_pa; + unsigned int cfg_table_len; + int ret; + + ret = efi_get_conf_table(bp, &cfg_table_pa, &cfg_table_len); + if (ret) + return NULL; + + return (struct cc_blob_sev_info *)efi_find_vendor_table(bp, cfg_table_pa, + cfg_table_len, + EFI_CC_BLOB_GUID); +} + +/* + * Initial set up of SNP relies on information provided by the + * Confidential Computing blob, which can be passed to the boot kernel + * by firmware/bootloader in the following ways: + * + * - via an entry in the EFI config table + * - via a setup_data structure, as defined by the Linux Boot Protocol + * + * Scan for the blob in that order. + */ +static struct cc_blob_sev_info *find_cc_blob(struct boot_params *bp) +{ + struct cc_blob_sev_info *cc_info; + + cc_info = find_cc_blob_efi(bp); + if (cc_info) + goto found_cc_info; + + cc_info = find_cc_blob_setup_data(bp); + if (!cc_info) + return NULL; + +found_cc_info: + if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC) + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED); + + return cc_info; +} + +/* + * Indicate SNP based on presence of SNP-specific CC blob. Subsequent checks + * will verify the SNP CPUID/MSR bits. + */ +static bool early_snp_init(struct boot_params *bp) +{ + struct cc_blob_sev_info *cc_info; + + if (!bp) + return false; + + cc_info = find_cc_blob(bp); + if (!cc_info) + return false; + + /* + * If a SNP-specific Confidential Computing blob is present, then + * firmware/bootloader have indicated SNP support. Verifying this + * involves CPUID checks which will be more reliable if the SNP + * CPUID table is used. See comments over snp_setup_cpuid_table() for + * more details. + */ + setup_cpuid_table(cc_info); + + /* + * Record the SVSM Calling Area (CA) address if the guest is not + * running at VMPL0. The CA will be used to communicate with the + * SVSM and request its services. + */ + svsm_setup_ca(cc_info); + + /* + * Pass run-time kernel a pointer to CC info via boot_params so EFI + * config table doesn't need to be searched again during early startup + * phase. + */ + bp->cc_blob_address = (u32)(unsigned long)cc_info; + + return true; +} + /* * sev_check_cpu_support - Check for SEV support in the CPU capabilities * @@ -463,7 +568,7 @@ void sev_enable(struct boot_params *bp) bp->cc_blob_address = 0; /* - * Do an initial SEV capability check before snp_init() which + * Do an initial SEV capability check before early_snp_init() which * loads the CPUID page and the same checks afterwards are done * without the hypervisor and are trustworthy. * @@ -478,7 +583,7 @@ void sev_enable(struct boot_params *bp) * Setup/preliminary detection of SNP. This will be sanity-checked * against CPUID/MSR values later. */ - snp = snp_init(bp); + snp = early_snp_init(bp); /* Now repeat the checks with the SNP CPUID table. */ @@ -506,10 +611,32 @@ void sev_enable(struct boot_params *bp) * features. */ if (sev_status & MSR_AMD64_SEV_SNP_ENABLED) { - if (!(get_hv_features() & GHCB_HV_FT_SNP)) + u64 hv_features; + int ret; + + hv_features = get_hv_features(); + if (!(hv_features & GHCB_HV_FT_SNP)) sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED); - enforce_vmpl0(); + /* + * Enforce running at VMPL0 or with an SVSM. + * + * Use RMPADJUST (see the rmpadjust() function for a description of + * what the instruction does) to update the VMPL1 permissions of a + * page. If the guest is running at VMPL0, this will succeed. If the + * guest is running at any other VMPL, this will fail. Linux SNP guests + * only ever run at a single VMPL level so permission mask changes of a + * lesser-privileged VMPL are a don't-care. + */ + ret = rmpadjust((unsigned long)&boot_ghcb_page, RMP_PG_SIZE_4K, 1); + + /* + * Running at VMPL0 is not required if an SVSM is present and the hypervisor + * supports the required SVSM GHCB events. + */ + if (ret && + !(snp_vmpl && (hv_features & GHCB_HV_FT_SNP_MULTI_VMPL))) + sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0); } if (snp && !(sev_status & MSR_AMD64_SEV_SNP_ENABLED)) @@ -535,85 +662,6 @@ u64 sev_get_status(void) return m.q; } -/* Search for Confidential Computing blob in the EFI config table. */ -static struct cc_blob_sev_info *find_cc_blob_efi(struct boot_params *bp) -{ - unsigned long cfg_table_pa; - unsigned int cfg_table_len; - int ret; - - ret = efi_get_conf_table(bp, &cfg_table_pa, &cfg_table_len); - if (ret) - return NULL; - - return (struct cc_blob_sev_info *)efi_find_vendor_table(bp, cfg_table_pa, - cfg_table_len, - EFI_CC_BLOB_GUID); -} - -/* - * Initial set up of SNP relies on information provided by the - * Confidential Computing blob, which can be passed to the boot kernel - * by firmware/bootloader in the following ways: - * - * - via an entry in the EFI config table - * - via a setup_data structure, as defined by the Linux Boot Protocol - * - * Scan for the blob in that order. - */ -static struct cc_blob_sev_info *find_cc_blob(struct boot_params *bp) -{ - struct cc_blob_sev_info *cc_info; - - cc_info = find_cc_blob_efi(bp); - if (cc_info) - goto found_cc_info; - - cc_info = find_cc_blob_setup_data(bp); - if (!cc_info) - return NULL; - -found_cc_info: - if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC) - sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED); - - return cc_info; -} - -/* - * Indicate SNP based on presence of SNP-specific CC blob. Subsequent checks - * will verify the SNP CPUID/MSR bits. - */ -bool snp_init(struct boot_params *bp) -{ - struct cc_blob_sev_info *cc_info; - - if (!bp) - return false; - - cc_info = find_cc_blob(bp); - if (!cc_info) - return false; - - /* - * If a SNP-specific Confidential Computing blob is present, then - * firmware/bootloader have indicated SNP support. Verifying this - * involves CPUID checks which will be more reliable if the SNP - * CPUID table is used. See comments over snp_setup_cpuid_table() for - * more details. - */ - setup_cpuid_table(cc_info); - - /* - * Pass run-time kernel a pointer to CC info via boot_params so EFI - * config table doesn't need to be searched again during early startup - * phase. - */ - bp->cc_blob_address = (u32)(unsigned long)cc_info; - - return true; -} - void sev_prep_identity_maps(unsigned long top_level_pgt) { /* |