Message ID | 20240215113128.275608-11-nikunj@amd.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | Add Secure TSC support for SNP guests | expand |
On Thu, Feb 15, 2024 at 05:01:22PM +0530, Nikunj A Dadhania wrote: > Add support for Secure TSC in SNP enabled guests. Secure TSC allows > guest to securely use RDTSC/RDTSCP instructions as the parameters > being used cannot be changed by hypervisor once the guest is launched. > > During the boot-up of the secondary cpus, SecureTSC enabled guests "CPUs" > need to query TSC info from AMD Security Processor. This communication > channel is encrypted between the AMD Security Processor and the guest, > the hypervisor is just the conduit to deliver the guest messages to > the AMD Security Processor. Each message is protected with an > AEAD (AES-256 GCM). Use minimal AES GCM library to encrypt/decrypt SNP > Guest messages to communicate with the PSP. > > Use the guest enc_init hook to fetch SNP TSC info from the AMD Security > Processor and initialize the snp_tsc_scale and snp_tsc_offset. During > secondary CPU initialization set VMSA fields GUEST_TSC_SCALE (offset 2F0h) > and GUEST_TSC_OFFSET(offset 2F8h) with snp_tsc_scale and snp_tsc_offset > respectively. > > Signed-off-by: Nikunj A Dadhania <nikunj@amd.com> > Tested-by: Peter Gonda <pgonda@google.com> > --- > arch/x86/include/asm/sev-common.h | 1 + > arch/x86/include/asm/sev.h | 23 +++++++ > arch/x86/include/asm/svm.h | 6 +- > arch/x86/kernel/sev.c | 107 ++++++++++++++++++++++++++++-- > arch/x86/mm/mem_encrypt_amd.c | 6 ++ > 5 files changed, 134 insertions(+), 9 deletions(-) > > diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h > index b463fcbd4b90..6adc8e27feeb 100644 > --- a/arch/x86/include/asm/sev-common.h > +++ b/arch/x86/include/asm/sev-common.h > @@ -159,6 +159,7 @@ struct snp_psc_desc { > #define GHCB_TERM_NOT_VMPL0 3 /* SNP guest is not running at VMPL-0 */ > #define GHCB_TERM_CPUID 4 /* CPUID-validation failure */ > #define GHCB_TERM_CPUID_HV 5 /* CPUID failure during hypervisor fallback */ > +#define GHCB_TERM_SECURE_TSC 6 /* Secure TSC initialization failed */ > > #define GHCB_RESP_CODE(v) ((v) & GHCB_MSR_INFO_MASK) > > diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h > index d950a3ac5694..16bf5afa7731 100644 > --- a/arch/x86/include/asm/sev.h > +++ b/arch/x86/include/asm/sev.h > @@ -170,6 +170,8 @@ enum msg_type { > SNP_MSG_ABSORB_RSP, > SNP_MSG_VMRK_REQ, > SNP_MSG_VMRK_RSP, <-- Pls leave an empty newline here to denote that there's a hole in the define numbers. Alternatively, you can add the missing ones too. > + SNP_MSG_TSC_INFO_REQ = 17, > + SNP_MSG_TSC_INFO_RSP, > > SNP_MSG_TYPE_MAX > }; > @@ -214,6 +216,23 @@ struct sev_guest_platform_data { > struct snp_req_data input; > }; > > +#define SNP_TSC_INFO_REQ_SZ 128 > + > +struct snp_tsc_info_req { > + /* Must be zero filled */ Instead of adding a comment which people might very likely miss, add a check for that array to warn when it is not zeroed. > + u8 rsvd[SNP_TSC_INFO_REQ_SZ]; > +} __packed; > + > +struct snp_tsc_info_resp { > + /* Status of TSC_INFO message */ The other struct members don't need a comment? > + u32 status; > + u32 rsvd1; > + u64 tsc_scale; > + u64 tsc_offset; > + u32 tsc_factor; > + u8 rsvd2[100]; > +} __packed; > + > struct snp_guest_dev { > struct device *dev; > struct miscdevice misc; > @@ -233,6 +252,7 @@ struct snp_guest_dev { > struct snp_report_req report; > struct snp_derived_key_req derived_key; > struct snp_ext_report_req ext_report; > + struct snp_tsc_info_req tsc_info; > } req; > unsigned int vmpck_id; > }; > @@ -370,6 +390,8 @@ static inline void *alloc_shared_pages(size_t sz) > > return page_address(page); > } > + > +void __init snp_secure_tsc_prepare(void); > #else > static inline void sev_es_ist_enter(struct pt_regs *regs) { } > static inline void sev_es_ist_exit(void) { } > @@ -404,6 +426,7 @@ static inline int snp_send_guest_request(struct snp_guest_dev *dev, struct snp_g > struct snp_guest_request_ioctl *rio) { return 0; } > static inline void free_shared_pages(void *buf, size_t sz) { } > static inline void *alloc_shared_pages(size_t sz) { return NULL; } > +static inline void __init snp_secure_tsc_prepare(void) { } > #endif > > #ifdef CONFIG_KVM_AMD_SEV > diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h > index 87a7b917d30e..3a8294bbd109 100644 > --- a/arch/x86/include/asm/svm.h > +++ b/arch/x86/include/asm/svm.h > @@ -410,7 +410,9 @@ struct sev_es_save_area { > u8 reserved_0x298[80]; > u32 pkru; > u32 tsc_aux; > - u8 reserved_0x2f0[24]; > + u64 tsc_scale; > + u64 tsc_offset; > + u8 reserved_0x300[8]; > u64 rcx; > u64 rdx; > u64 rbx; > @@ -542,7 +544,7 @@ static inline void __unused_size_checks(void) > BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x1c0); > BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x248); > BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x298); > - BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x2f0); > + BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x300); > BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x320); > BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x380); > BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x3f0); > diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c > index a9c1efd6d4e3..20a1e50b7638 100644 > --- a/arch/x86/kernel/sev.c > +++ b/arch/x86/kernel/sev.c > @@ -75,6 +75,10 @@ static u64 sev_hv_features __ro_after_init; > /* Secrets page physical address from the CC blob */ > static u64 secrets_pa __ro_after_init; > > +/* Secure TSC values read using TSC_INFO SNP Guest request */ > +static u64 snp_tsc_scale __ro_after_init; > +static u64 snp_tsc_offset __ro_after_init; > + > /* #VC handler runtime per-CPU data */ > struct sev_es_runtime_data { > struct ghcb ghcb_page; > @@ -956,6 +960,83 @@ void snp_guest_cmd_unlock(void) > } > EXPORT_SYMBOL_GPL(snp_guest_cmd_unlock); > > +static struct snp_guest_dev tsc_snp_dev __initdata; > + > +static int __snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req, > + struct snp_guest_request_ioctl *rio); > + Pls design your code without the need for a forward declaration. > +static int __init snp_get_tsc_info(void) > +{ > + struct snp_tsc_info_req *tsc_req = &tsc_snp_dev.req.tsc_info; > + static u8 buf[SNP_TSC_INFO_REQ_SZ + AUTHTAG_LEN]; > + struct snp_guest_request_ioctl rio; > + struct snp_tsc_info_resp tsc_resp; > + struct snp_guest_req req; > + int rc, resp_len; > + > + /* > + * The intermediate response buffer is used while decrypting the > + * response payload. Make sure that it has enough space to cover the > + * authtag. > + */ > + resp_len = sizeof(tsc_resp) + AUTHTAG_LEN; > + if (sizeof(buf) < resp_len) > + return -EINVAL; Huh, those both are static buffers. Such checks are done with BUILD_BUG_ON. > + memset(tsc_req, 0, sizeof(*tsc_req)); > + memset(&req, 0, sizeof(req)); > + memset(&rio, 0, sizeof(rio)); > + memset(buf, 0, sizeof(buf)); > + > + if (!snp_assign_vmpck(&tsc_snp_dev, 0)) > + return -EINVAL; Do that before the memsetting. > + > + /* Initialize the PSP channel to send snp messages */ > + rc = snp_setup_psp_messaging(&tsc_snp_dev); > + if (rc) > + return rc; > + > + req.msg_version = MSG_HDR_VER; > + req.msg_type = SNP_MSG_TSC_INFO_REQ; > + req.vmpck_id = tsc_snp_dev.vmpck_id; > + req.req_buf = tsc_req; > + req.req_sz = sizeof(*tsc_req); > + req.resp_buf = buf; > + req.resp_sz = resp_len; > + req.exit_code = SVM_VMGEXIT_GUEST_REQUEST; > + > + rc = __snp_send_guest_request(&tsc_snp_dev, &req, &rio); The changes to *snp_send_guest_request are unrelated to the secure TSC enablement. Pls do them in a pre-patch. Ok, I'm going to stop here and give you a chance to work in all the review feedback and send a new revision. Thx.
On 4/22/2024 7:20 PM, Borislav Petkov wrote: > On Thu, Feb 15, 2024 at 05:01:22PM +0530, Nikunj A Dadhania wrote: >> Add support for Secure TSC in SNP enabled guests. Secure TSC allows >> guest to securely use RDTSC/RDTSCP instructions as the parameters >> being used cannot be changed by hypervisor once the guest is launched. >> >> During the boot-up of the secondary cpus, SecureTSC enabled guests > > "CPUs" Sure >> need to query TSC info from AMD Security Processor. This communication >> channel is encrypted between the AMD Security Processor and the guest, >> the hypervisor is just the conduit to deliver the guest messages to >> the AMD Security Processor. Each message is protected with an >> AEAD (AES-256 GCM). Use minimal AES GCM library to encrypt/decrypt SNP >> Guest messages to communicate with the PSP. >> >> Use the guest enc_init hook to fetch SNP TSC info from the AMD Security >> Processor and initialize the snp_tsc_scale and snp_tsc_offset. During >> secondary CPU initialization set VMSA fields GUEST_TSC_SCALE (offset 2F0h) >> and GUEST_TSC_OFFSET(offset 2F8h) with snp_tsc_scale and snp_tsc_offset >> respectively. >> >> Signed-off-by: Nikunj A Dadhania <nikunj@amd.com> >> Tested-by: Peter Gonda <pgonda@google.com> >> --- >> arch/x86/include/asm/sev-common.h | 1 + >> arch/x86/include/asm/sev.h | 23 +++++++ >> arch/x86/include/asm/svm.h | 6 +- >> arch/x86/kernel/sev.c | 107 ++++++++++++++++++++++++++++-- >> arch/x86/mm/mem_encrypt_amd.c | 6 ++ >> 5 files changed, 134 insertions(+), 9 deletions(-) >> >> diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h >> index b463fcbd4b90..6adc8e27feeb 100644 >> --- a/arch/x86/include/asm/sev-common.h >> +++ b/arch/x86/include/asm/sev-common.h >> @@ -159,6 +159,7 @@ struct snp_psc_desc { >> #define GHCB_TERM_NOT_VMPL0 3 /* SNP guest is not running at VMPL-0 */ >> #define GHCB_TERM_CPUID 4 /* CPUID-validation failure */ >> #define GHCB_TERM_CPUID_HV 5 /* CPUID failure during hypervisor fallback */ >> +#define GHCB_TERM_SECURE_TSC 6 /* Secure TSC initialization failed */ >> >> #define GHCB_RESP_CODE(v) ((v) & GHCB_MSR_INFO_MASK) >> >> diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h >> index d950a3ac5694..16bf5afa7731 100644 >> --- a/arch/x86/include/asm/sev.h >> +++ b/arch/x86/include/asm/sev.h >> @@ -170,6 +170,8 @@ enum msg_type { >> SNP_MSG_ABSORB_RSP, >> SNP_MSG_VMRK_REQ, >> SNP_MSG_VMRK_RSP, > > <-- Pls leave an empty newline here to denote that there's a hole in the > define numbers. Alternatively, you can add the missing ones too. I will add empty line. >> + SNP_MSG_TSC_INFO_REQ = 17, >> + SNP_MSG_TSC_INFO_RSP, >> >> SNP_MSG_TYPE_MAX >> }; >> @@ -214,6 +216,23 @@ struct sev_guest_platform_data { >> struct snp_req_data input; >> }; >> >> +#define SNP_TSC_INFO_REQ_SZ 128 >> + >> +struct snp_tsc_info_req { >> + /* Must be zero filled */ > > Instead of adding a comment which people might very likely miss, add > a check for that array to warn when it is not zeroed. Sure. > >> + u8 rsvd[SNP_TSC_INFO_REQ_SZ]; >> +} __packed; >> + >> +struct snp_tsc_info_resp { >> + /* Status of TSC_INFO message */ > > The other struct members don't need a comment? Sure. >> + u32 status; >> + u32 rsvd1; >> + u64 tsc_scale; >> + u64 tsc_offset; >> + u32 tsc_factor; >> + u8 rsvd2[100]; >> +} __packed; >> + >> struct snp_guest_dev { >> struct device *dev; >> struct miscdevice misc; >> @@ -233,6 +252,7 @@ struct snp_guest_dev { >> struct snp_report_req report; >> struct snp_derived_key_req derived_key; >> struct snp_ext_report_req ext_report; >> + struct snp_tsc_info_req tsc_info; >> } req; >> unsigned int vmpck_id; >> }; >> @@ -370,6 +390,8 @@ static inline void *alloc_shared_pages(size_t sz) >> >> return page_address(page); >> } >> + >> +void __init snp_secure_tsc_prepare(void); >> #else >> static inline void sev_es_ist_enter(struct pt_regs *regs) { } >> static inline void sev_es_ist_exit(void) { } >> @@ -404,6 +426,7 @@ static inline int snp_send_guest_request(struct snp_guest_dev *dev, struct snp_g >> struct snp_guest_request_ioctl *rio) { return 0; } >> static inline void free_shared_pages(void *buf, size_t sz) { } >> static inline void *alloc_shared_pages(size_t sz) { return NULL; } >> +static inline void __init snp_secure_tsc_prepare(void) { } >> #endif >> >> #ifdef CONFIG_KVM_AMD_SEV >> diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h >> index 87a7b917d30e..3a8294bbd109 100644 >> --- a/arch/x86/include/asm/svm.h >> +++ b/arch/x86/include/asm/svm.h >> @@ -410,7 +410,9 @@ struct sev_es_save_area { >> u8 reserved_0x298[80]; >> u32 pkru; >> u32 tsc_aux; >> - u8 reserved_0x2f0[24]; >> + u64 tsc_scale; >> + u64 tsc_offset; >> + u8 reserved_0x300[8]; >> u64 rcx; >> u64 rdx; >> u64 rbx; >> @@ -542,7 +544,7 @@ static inline void __unused_size_checks(void) >> BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x1c0); >> BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x248); >> BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x298); >> - BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x2f0); >> + BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x300); >> BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x320); >> BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x380); >> BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x3f0); >> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c >> index a9c1efd6d4e3..20a1e50b7638 100644 >> --- a/arch/x86/kernel/sev.c >> +++ b/arch/x86/kernel/sev.c >> @@ -75,6 +75,10 @@ static u64 sev_hv_features __ro_after_init; >> /* Secrets page physical address from the CC blob */ >> static u64 secrets_pa __ro_after_init; >> >> +/* Secure TSC values read using TSC_INFO SNP Guest request */ >> +static u64 snp_tsc_scale __ro_after_init; >> +static u64 snp_tsc_offset __ro_after_init; >> + >> /* #VC handler runtime per-CPU data */ >> struct sev_es_runtime_data { >> struct ghcb ghcb_page; >> @@ -956,6 +960,83 @@ void snp_guest_cmd_unlock(void) >> } >> EXPORT_SYMBOL_GPL(snp_guest_cmd_unlock); >> >> +static struct snp_guest_dev tsc_snp_dev __initdata; >> + >> +static int __snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req, >> + struct snp_guest_request_ioctl *rio); >> + > > Pls design your code without the need for a forward declaration. Sure > >> +static int __init snp_get_tsc_info(void) >> +{ >> + struct snp_tsc_info_req *tsc_req = &tsc_snp_dev.req.tsc_info; >> + static u8 buf[SNP_TSC_INFO_REQ_SZ + AUTHTAG_LEN]; >> + struct snp_guest_request_ioctl rio; >> + struct snp_tsc_info_resp tsc_resp; >> + struct snp_guest_req req; >> + int rc, resp_len; >> + >> + /* >> + * The intermediate response buffer is used while decrypting the >> + * response payload. Make sure that it has enough space to cover the >> + * authtag. >> + */ >> + resp_len = sizeof(tsc_resp) + AUTHTAG_LEN; >> + if (sizeof(buf) < resp_len) >> + return -EINVAL; > > Huh, those both are static buffers. Such checks are done with > BUILD_BUG_ON. Ok > >> + memset(tsc_req, 0, sizeof(*tsc_req)); >> + memset(&req, 0, sizeof(req)); >> + memset(&rio, 0, sizeof(rio)); >> + memset(buf, 0, sizeof(buf)); >> + >> + if (!snp_assign_vmpck(&tsc_snp_dev, 0)) >> + return -EINVAL; > > Do that before the memsetting. > Sure >> + >> + /* Initialize the PSP channel to send snp messages */ >> + rc = snp_setup_psp_messaging(&tsc_snp_dev); >> + if (rc) >> + return rc; >> + >> + req.msg_version = MSG_HDR_VER; >> + req.msg_type = SNP_MSG_TSC_INFO_REQ; >> + req.vmpck_id = tsc_snp_dev.vmpck_id; >> + req.req_buf = tsc_req; >> + req.req_sz = sizeof(*tsc_req); >> + req.resp_buf = buf; >> + req.resp_sz = resp_len; >> + req.exit_code = SVM_VMGEXIT_GUEST_REQUEST; >> + >> + rc = __snp_send_guest_request(&tsc_snp_dev, &req, &rio); > > The changes to *snp_send_guest_request are unrelated to the secure TSC > enablement. Pls do them in a pre-patch. Sure > > Ok, I'm going to stop here and give you a chance to work in all the > review feedback and send a new revision. Thank you for detailed review/feedback, will address them and send new revision. Regards Nikunj
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h index b463fcbd4b90..6adc8e27feeb 100644 --- a/arch/x86/include/asm/sev-common.h +++ b/arch/x86/include/asm/sev-common.h @@ -159,6 +159,7 @@ struct snp_psc_desc { #define GHCB_TERM_NOT_VMPL0 3 /* SNP guest is not running at VMPL-0 */ #define GHCB_TERM_CPUID 4 /* CPUID-validation failure */ #define GHCB_TERM_CPUID_HV 5 /* CPUID failure during hypervisor fallback */ +#define GHCB_TERM_SECURE_TSC 6 /* Secure TSC initialization failed */ #define GHCB_RESP_CODE(v) ((v) & GHCB_MSR_INFO_MASK) diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index d950a3ac5694..16bf5afa7731 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -170,6 +170,8 @@ enum msg_type { SNP_MSG_ABSORB_RSP, SNP_MSG_VMRK_REQ, SNP_MSG_VMRK_RSP, + SNP_MSG_TSC_INFO_REQ = 17, + SNP_MSG_TSC_INFO_RSP, SNP_MSG_TYPE_MAX }; @@ -214,6 +216,23 @@ struct sev_guest_platform_data { struct snp_req_data input; }; +#define SNP_TSC_INFO_REQ_SZ 128 + +struct snp_tsc_info_req { + /* Must be zero filled */ + u8 rsvd[SNP_TSC_INFO_REQ_SZ]; +} __packed; + +struct snp_tsc_info_resp { + /* Status of TSC_INFO message */ + u32 status; + u32 rsvd1; + u64 tsc_scale; + u64 tsc_offset; + u32 tsc_factor; + u8 rsvd2[100]; +} __packed; + struct snp_guest_dev { struct device *dev; struct miscdevice misc; @@ -233,6 +252,7 @@ struct snp_guest_dev { struct snp_report_req report; struct snp_derived_key_req derived_key; struct snp_ext_report_req ext_report; + struct snp_tsc_info_req tsc_info; } req; unsigned int vmpck_id; }; @@ -370,6 +390,8 @@ static inline void *alloc_shared_pages(size_t sz) return page_address(page); } + +void __init snp_secure_tsc_prepare(void); #else static inline void sev_es_ist_enter(struct pt_regs *regs) { } static inline void sev_es_ist_exit(void) { } @@ -404,6 +426,7 @@ static inline int snp_send_guest_request(struct snp_guest_dev *dev, struct snp_g struct snp_guest_request_ioctl *rio) { return 0; } static inline void free_shared_pages(void *buf, size_t sz) { } static inline void *alloc_shared_pages(size_t sz) { return NULL; } +static inline void __init snp_secure_tsc_prepare(void) { } #endif #ifdef CONFIG_KVM_AMD_SEV diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h index 87a7b917d30e..3a8294bbd109 100644 --- a/arch/x86/include/asm/svm.h +++ b/arch/x86/include/asm/svm.h @@ -410,7 +410,9 @@ struct sev_es_save_area { u8 reserved_0x298[80]; u32 pkru; u32 tsc_aux; - u8 reserved_0x2f0[24]; + u64 tsc_scale; + u64 tsc_offset; + u8 reserved_0x300[8]; u64 rcx; u64 rdx; u64 rbx; @@ -542,7 +544,7 @@ static inline void __unused_size_checks(void) BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x1c0); BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x248); BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x298); - BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x2f0); + BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x300); BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x320); BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x380); BUILD_BUG_RESERVED_OFFSET(sev_es_save_area, 0x3f0); diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index a9c1efd6d4e3..20a1e50b7638 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -75,6 +75,10 @@ static u64 sev_hv_features __ro_after_init; /* Secrets page physical address from the CC blob */ static u64 secrets_pa __ro_after_init; +/* Secure TSC values read using TSC_INFO SNP Guest request */ +static u64 snp_tsc_scale __ro_after_init; +static u64 snp_tsc_offset __ro_after_init; + /* #VC handler runtime per-CPU data */ struct sev_es_runtime_data { struct ghcb ghcb_page; @@ -956,6 +960,83 @@ void snp_guest_cmd_unlock(void) } EXPORT_SYMBOL_GPL(snp_guest_cmd_unlock); +static struct snp_guest_dev tsc_snp_dev __initdata; + +static int __snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req, + struct snp_guest_request_ioctl *rio); + +static int __init snp_get_tsc_info(void) +{ + struct snp_tsc_info_req *tsc_req = &tsc_snp_dev.req.tsc_info; + static u8 buf[SNP_TSC_INFO_REQ_SZ + AUTHTAG_LEN]; + struct snp_guest_request_ioctl rio; + struct snp_tsc_info_resp tsc_resp; + struct snp_guest_req req; + int rc, resp_len; + + /* + * The intermediate response buffer is used while decrypting the + * response payload. Make sure that it has enough space to cover the + * authtag. + */ + resp_len = sizeof(tsc_resp) + AUTHTAG_LEN; + if (sizeof(buf) < resp_len) + return -EINVAL; + + memset(tsc_req, 0, sizeof(*tsc_req)); + memset(&req, 0, sizeof(req)); + memset(&rio, 0, sizeof(rio)); + memset(buf, 0, sizeof(buf)); + + if (!snp_assign_vmpck(&tsc_snp_dev, 0)) + return -EINVAL; + + /* Initialize the PSP channel to send snp messages */ + rc = snp_setup_psp_messaging(&tsc_snp_dev); + if (rc) + return rc; + + req.msg_version = MSG_HDR_VER; + req.msg_type = SNP_MSG_TSC_INFO_REQ; + req.vmpck_id = tsc_snp_dev.vmpck_id; + req.req_buf = tsc_req; + req.req_sz = sizeof(*tsc_req); + req.resp_buf = buf; + req.resp_sz = resp_len; + req.exit_code = SVM_VMGEXIT_GUEST_REQUEST; + + rc = __snp_send_guest_request(&tsc_snp_dev, &req, &rio); + if (rc) + goto err_req; + + memcpy(&tsc_resp, buf, sizeof(tsc_resp)); + pr_debug("%s: Valid response status %x scale %llx offset %llx factor %x\n", + __func__, tsc_resp.status, tsc_resp.tsc_scale, tsc_resp.tsc_offset, + tsc_resp.tsc_factor); + + snp_tsc_scale = tsc_resp.tsc_scale; + snp_tsc_offset = tsc_resp.tsc_offset; + +err_req: + /* The response buffer contains the sensitive data, explicitly clear it. */ + memzero_explicit(buf, sizeof(buf)); + memzero_explicit(&tsc_resp, sizeof(tsc_resp)); + memzero_explicit(&req, sizeof(req)); + + return rc; +} + +void __init snp_secure_tsc_prepare(void) +{ + if (!cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC)) + return; + + if (snp_get_tsc_info()) + sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SECURE_TSC); + + pr_debug("SecureTSC enabled\n"); +} + static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip) { struct sev_es_save_area *cur_vmsa, *vmsa; @@ -1056,6 +1137,12 @@ static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip) vmsa->vmpl = 0; vmsa->sev_features = sev_status >> 2; + /* Setting Secure TSC parameters */ + if (cpu_feature_enabled(X86_FEATURE_SNP_SECURE_TSC)) { + vmsa->tsc_scale = snp_tsc_scale; + vmsa->tsc_offset = snp_tsc_offset; + } + /* Switch the page over to a VMSA page now that it is initialized */ ret = snp_set_vmsa(vmsa, true); if (ret) { @@ -2638,18 +2725,13 @@ static int __handle_guest_request(struct snp_guest_dev *snp_dev, struct snp_gues return rc; } -int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req, - struct snp_guest_request_ioctl *rio) +static int __snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req, + struct snp_guest_request_ioctl *rio) { struct sev_guest_platform_data *pdata; u64 seqno; int rc; - if (!snp_dev || !snp_dev->pdata || !req || !rio) - return -ENODEV; - - lockdep_assert_held(&snp_guest_cmd_mutex); - pdata = snp_dev->pdata; /* Get message sequence and verify that its a non-zero */ @@ -2692,6 +2774,17 @@ int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req * return 0; } + +int snp_send_guest_request(struct snp_guest_dev *snp_dev, struct snp_guest_req *req, + struct snp_guest_request_ioctl *rio) +{ + if (!snp_dev || !snp_dev->pdata || !req || !rio) + return -ENODEV; + + lockdep_assert_held(&snp_guest_cmd_mutex); + + return __snp_send_guest_request(snp_dev, req, rio); +} EXPORT_SYMBOL_GPL(snp_send_guest_request); bool snp_assign_vmpck(struct snp_guest_dev *dev, unsigned int vmpck_id) diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c index 70b91de2e053..c81b57ca03b6 100644 --- a/arch/x86/mm/mem_encrypt_amd.c +++ b/arch/x86/mm/mem_encrypt_amd.c @@ -214,6 +214,11 @@ void __init sme_map_bootdata(char *real_mode_data) __sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, true); } +static void __init amd_enc_init(void) +{ + snp_secure_tsc_prepare(); +} + static unsigned long pg_level_to_pfn(int level, pte_t *kpte, pgprot_t *ret_prot) { unsigned long pfn = 0; @@ -467,6 +472,7 @@ void __init sme_early_init(void) x86_platform.guest.enc_status_change_finish = amd_enc_status_change_finish; x86_platform.guest.enc_tlb_flush_required = amd_enc_tlb_flush_required; x86_platform.guest.enc_cache_flush_required = amd_enc_cache_flush_required; + x86_platform.guest.enc_init = amd_enc_init; /* * AMD-SEV-ES intercepts the RDMSR to read the X2APIC ID in the