diff options
author | Brijesh Singh <brijesh.singh@amd.com> | 2022-03-07 15:33:51 -0600 |
---|---|---|
committer | Borislav Petkov <bp@suse.de> | 2022-04-07 16:47:12 +0200 |
commit | d5af44dde5461d125d1602ac913ab5c6bdf09b8b (patch) | |
tree | 37b7a764183747cb3a64700efe4b9ea5eac913e6 | |
parent | ba37a1438aeb540cc48722d629f4b2e7e4398466 (diff) |
x86/sev: Provide support for SNP guest request NAEs
Version 2 of GHCB specification provides SNP_GUEST_REQUEST and
SNP_EXT_GUEST_REQUEST NAE that can be used by the SNP guest to
communicate with the PSP.
While at it, add a snp_issue_guest_request() helper that will be used by
driver or other subsystem to issue the request to PSP.
See SEV-SNP firmware and GHCB spec for more details.
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-42-brijesh.singh@amd.com
-rw-r--r-- | arch/x86/include/asm/sev-common.h | 3 | ||||
-rw-r--r-- | arch/x86/include/asm/sev.h | 14 | ||||
-rw-r--r-- | arch/x86/include/uapi/asm/svm.h | 4 | ||||
-rw-r--r-- | arch/x86/kernel/sev.c | 57 |
4 files changed, 78 insertions, 0 deletions
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h index 0759af9b1acf..b8357d6ecd47 100644 --- a/arch/x86/include/asm/sev-common.h +++ b/arch/x86/include/asm/sev-common.h @@ -128,6 +128,9 @@ struct snp_psc_desc { struct psc_entry entries[VMGEXIT_PSC_MAX_ENTRY]; } __packed; +/* Guest message request error code */ +#define SNP_GUEST_REQ_INVALID_LEN BIT_ULL(32) + #define GHCB_MSR_TERM_REQ 0x100 #define GHCB_MSR_TERM_REASON_SET_POS 12 #define GHCB_MSR_TERM_REASON_SET_MASK 0xf diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index 84d3d5121e9c..c63a1d485c20 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -87,6 +87,14 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs); #define RMPADJUST_VMSA_PAGE_BIT BIT(16) +/* SNP Guest message request */ +struct snp_req_data { + unsigned long req_gpa; + unsigned long resp_gpa; + unsigned long data_gpa; + unsigned int data_npages; +}; + #ifdef CONFIG_AMD_MEM_ENCRYPT extern struct static_key_false sev_es_enable_key; extern void __sev_es_ist_enter(struct pt_regs *regs); @@ -154,6 +162,7 @@ void snp_set_memory_private(unsigned long vaddr, unsigned int npages); void snp_set_wakeup_secondary_cpu(void); bool snp_init(struct boot_params *bp); void snp_abort(void); +int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err); #else static inline void sev_es_ist_enter(struct pt_regs *regs) { } static inline void sev_es_ist_exit(void) { } @@ -173,6 +182,11 @@ static inline void snp_set_memory_private(unsigned long vaddr, unsigned int npag static inline void snp_set_wakeup_secondary_cpu(void) { } static inline bool snp_init(struct boot_params *bp) { return false; } static inline void snp_abort(void) { } +static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, + unsigned long *fw_err) +{ + return -ENOTTY; +} #endif #endif diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h index cfea5e875088..f69c168391aa 100644 --- a/arch/x86/include/uapi/asm/svm.h +++ b/arch/x86/include/uapi/asm/svm.h @@ -109,6 +109,8 @@ #define SVM_VMGEXIT_SET_AP_JUMP_TABLE 0 #define SVM_VMGEXIT_GET_AP_JUMP_TABLE 1 #define SVM_VMGEXIT_PSC 0x80000010 +#define SVM_VMGEXIT_GUEST_REQUEST 0x80000011 +#define SVM_VMGEXIT_EXT_GUEST_REQUEST 0x80000012 #define SVM_VMGEXIT_AP_CREATION 0x80000013 #define SVM_VMGEXIT_AP_CREATE_ON_INIT 0 #define SVM_VMGEXIT_AP_CREATE 1 @@ -225,6 +227,8 @@ { SVM_VMGEXIT_AP_HLT_LOOP, "vmgexit_ap_hlt_loop" }, \ { SVM_VMGEXIT_AP_JUMP_TABLE, "vmgexit_ap_jump_table" }, \ { SVM_VMGEXIT_PSC, "vmgexit_page_state_change" }, \ + { SVM_VMGEXIT_GUEST_REQUEST, "vmgexit_guest_request" }, \ + { SVM_VMGEXIT_EXT_GUEST_REQUEST, "vmgexit_ext_guest_request" }, \ { SVM_VMGEXIT_AP_CREATION, "vmgexit_ap_creation" }, \ { SVM_VMGEXIT_HV_FEATURES, "vmgexit_hypervisor_feature" }, \ { SVM_EXIT_ERR, "invalid_guest_state" } diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 70ecc6e2f251..7237b4178935 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -2106,3 +2106,60 @@ static int __init init_sev_config(char *str) return 1; } __setup("sev=", init_sev_config); + +int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err) +{ + struct ghcb_state state; + struct es_em_ctxt ctxt; + unsigned long flags; + struct ghcb *ghcb; + int ret; + + if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) + return -ENODEV; + + if (!fw_err) + return -EINVAL; + + /* + * __sev_get_ghcb() needs to run with IRQs disabled because it is using + * a per-CPU GHCB. + */ + local_irq_save(flags); + + ghcb = __sev_get_ghcb(&state); + if (!ghcb) { + ret = -EIO; + goto e_restore_irq; + } + + vc_ghcb_invalidate(ghcb); + + if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) { + ghcb_set_rax(ghcb, input->data_gpa); + ghcb_set_rbx(ghcb, input->data_npages); + } + + ret = sev_es_ghcb_hv_call(ghcb, true, &ctxt, exit_code, input->req_gpa, input->resp_gpa); + if (ret) + goto e_put; + + if (ghcb->save.sw_exit_info_2) { + /* Number of expected pages are returned in RBX */ + if (exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST && + ghcb->save.sw_exit_info_2 == SNP_GUEST_REQ_INVALID_LEN) + input->data_npages = ghcb_get_rbx(ghcb); + + *fw_err = ghcb->save.sw_exit_info_2; + + ret = -EIO; + } + +e_put: + __sev_put_ghcb(&state); +e_restore_irq: + local_irq_restore(flags); + + return ret; +} +EXPORT_SYMBOL_GPL(snp_issue_guest_request); |