| Message ID | 20210707181506.30489-6-brijesh.singh@amd.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | Add AMD Secure Nested Paging (SEV-SNP) Guest Support | expand |
On Wed, Jul 07, 2021 at 01:14:35PM -0500, Brijesh Singh wrote: > diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h > index 23929a3010df..e75e29c05f59 100644 > --- a/arch/x86/include/asm/sev-common.h > +++ b/arch/x86/include/asm/sev-common.h > @@ -63,9 +63,17 @@ > (((((u64)reason_set) & GHCB_MSR_TERM_REASON_SET_MASK) << GHCB_MSR_TERM_REASON_SET_POS) | \ > ((((u64)reason_val) & GHCB_MSR_TERM_REASON_MASK) << GHCB_MSR_TERM_REASON_POS)) > > +/* Error code from reason set 0 */ ... Error codes... > +#define SEV_TERM_SET_GEN 0 > #define GHCB_SEV_ES_GEN_REQ 0 > #define GHCB_SEV_ES_PROT_UNSUPPORTED 1 > > #define GHCB_RESP_CODE(v) ((v) & GHCB_MSR_INFO_MASK) > > +/* Linux specific reason codes (used with reason set 1) */ ... Linux-specific ... > +#define SEV_TERM_SET_LINUX 1 GHCB doc says: "This document defines and owns reason code set 0x0" Should it also say, reason code set 1 is allocated for Linux guest use? I don't see why not... Tom? > +#define GHCB_TERM_REGISTER 0 /* GHCB GPA registration failure */ > +#define GHCB_TERM_PSC 1 /* Page State Change failure */ > +#define GHCB_TERM_PVALIDATE 2 /* Pvalidate failure */ > + > #endif
On 8/10/21 6:33 AM, Borislav Petkov wrote: > On Wed, Jul 07, 2021 at 01:14:35PM -0500, Brijesh Singh wrote: >> diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h >> index 23929a3010df..e75e29c05f59 100644 >> --- a/arch/x86/include/asm/sev-common.h >> +++ b/arch/x86/include/asm/sev-common.h >> @@ -63,9 +63,17 @@ >> (((((u64)reason_set) & GHCB_MSR_TERM_REASON_SET_MASK) << GHCB_MSR_TERM_REASON_SET_POS) | \ >> ((((u64)reason_val) & GHCB_MSR_TERM_REASON_MASK) << GHCB_MSR_TERM_REASON_POS)) >> >> +/* Error code from reason set 0 */ > > ... Error codes... > Noted. >> +#define SEV_TERM_SET_GEN 0 >> #define GHCB_SEV_ES_GEN_REQ 0 >> #define GHCB_SEV_ES_PROT_UNSUPPORTED 1 >> >> #define GHCB_RESP_CODE(v) ((v) & GHCB_MSR_INFO_MASK) >> >> +/* Linux specific reason codes (used with reason set 1) */ > > ... Linux-specific ... Noted. > >> +#define SEV_TERM_SET_LINUX 1 > > GHCB doc says: > > "This document defines and owns reason code set 0x0" > > Should it also say, reason code set 1 is allocated for Linux guest use? > I don't see why not... > > Tom? > If Tom is okay with it then maybe in next version of the GHCB doc can add this text.
On 8/10/21 9:59 AM, Brijesh Singh wrote: > On 8/10/21 6:33 AM, Borislav Petkov wrote: >> On Wed, Jul 07, 2021 at 01:14:35PM -0500, Brijesh Singh wrote: >>> +#define SEV_TERM_SET_LINUX 1 >> >> GHCB doc says: >> >> "This document defines and owns reason code set 0x0" >> >> Should it also say, reason code set 1 is allocated for Linux guest use? >> I don't see why not... >> > Tom? >> > > If Tom is okay with it then maybe in next version of the GHCB doc can add > this text. IIRC, during the review of the first GHCB version there was discussion about assigning reason sets outside of 0 within the spec and the overall feeling was to not do that as part of the spec. We can re-open that discussion for the next version of the GHCB document. Thanks, Tom
On Tue, Aug 10, 2021 at 02:30:44PM -0500, Tom Lendacky wrote: > IIRC, during the review of the first GHCB version there was discussion > about assigning reason sets outside of 0 within the spec and the overall > feeling was to not do that as part of the spec. > > We can re-open that discussion for the next version of the GHCB document. My worry is that if nothing documents which sets are allocated to which vendor, it'll become a mess. Imagine a Linux SNP guest and a windoze one, both running on a KVM hypervisor (is that even possible?) and both using the same termination reason set with conflicting reason numbers. Unneeded confusion. Unless the spec says, "reason set 1 is allocated to Linux, set 2 to windoze, etc" Then all know which is which. And so on... Thx.
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c index 28bcf04c022e..7760959fe96d 100644 --- a/arch/x86/boot/compressed/sev.c +++ b/arch/x86/boot/compressed/sev.c @@ -122,7 +122,7 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt, static bool early_setup_sev_es(void) { if (!sev_es_negotiate_protocol()) - sev_es_terminate(GHCB_SEV_ES_PROT_UNSUPPORTED); + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_PROT_UNSUPPORTED); if (set_page_decrypted((unsigned long)&boot_ghcb_page)) return false; @@ -175,7 +175,7 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code) enum es_result result; if (!boot_ghcb && !early_setup_sev_es()) - sev_es_terminate(GHCB_SEV_ES_GEN_REQ); + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ); vc_ghcb_invalidate(boot_ghcb); result = vc_init_em_ctxt(&ctxt, regs, exit_code); @@ -202,5 +202,5 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code) if (result == ES_OK) vc_finish_insn(&ctxt); else if (result != ES_RETRY) - sev_es_terminate(GHCB_SEV_ES_GEN_REQ); + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ); } diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h index 23929a3010df..e75e29c05f59 100644 --- a/arch/x86/include/asm/sev-common.h +++ b/arch/x86/include/asm/sev-common.h @@ -63,9 +63,17 @@ (((((u64)reason_set) & GHCB_MSR_TERM_REASON_SET_MASK) << GHCB_MSR_TERM_REASON_SET_POS) | \ ((((u64)reason_val) & GHCB_MSR_TERM_REASON_MASK) << GHCB_MSR_TERM_REASON_POS)) +/* Error code from reason set 0 */ +#define SEV_TERM_SET_GEN 0 #define GHCB_SEV_ES_GEN_REQ 0 #define GHCB_SEV_ES_PROT_UNSUPPORTED 1 #define GHCB_RESP_CODE(v) ((v) & GHCB_MSR_INFO_MASK) +/* Linux specific reason codes (used with reason set 1) */ +#define SEV_TERM_SET_LINUX 1 +#define GHCB_TERM_REGISTER 0 /* GHCB GPA registration failure */ +#define GHCB_TERM_PSC 1 /* Page State Change failure */ +#define GHCB_TERM_PVALIDATE 2 /* Pvalidate failure */ + #endif diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c index 34821da5f05e..c54be2698df0 100644 --- a/arch/x86/kernel/sev-shared.c +++ b/arch/x86/kernel/sev-shared.c @@ -36,15 +36,12 @@ static bool __init sev_es_check_cpu_features(void) return true; } -static void __noreturn sev_es_terminate(unsigned int reason) +static void __noreturn sev_es_terminate(unsigned int set, unsigned int reason) { u64 val = GHCB_MSR_TERM_REQ; - /* - * Tell the hypervisor what went wrong - only reason-set 0 is - * currently supported. - */ - val |= GHCB_SEV_TERM_REASON(0, reason); + /* Tell the hypervisor what went wrong. */ + val |= GHCB_SEV_TERM_REASON(set, reason); /* Request Guest Termination from Hypvervisor */ sev_es_wr_ghcb_msr(val); @@ -242,7 +239,7 @@ void __init do_vc_no_ghcb(struct pt_regs *regs, unsigned long exit_code) fail: /* Terminate the guest */ - sev_es_terminate(GHCB_SEV_ES_GEN_REQ); + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ); } static enum es_result vc_insn_string_read(struct es_em_ctxt *ctxt, diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 540b81ac54c9..0245fe986615 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -1432,7 +1432,7 @@ DEFINE_IDTENTRY_VC_KERNEL(exc_vmm_communication) show_regs(regs); /* Ask hypervisor to sev_es_terminate */ - sev_es_terminate(GHCB_SEV_ES_GEN_REQ); + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ); /* If that fails and we get here - just panic */ panic("Returned from Terminate-Request to Hypervisor\n"); @@ -1480,7 +1480,7 @@ bool __init handle_vc_boot_ghcb(struct pt_regs *regs) /* Do initial setup or terminate the guest */ if (unlikely(boot_ghcb == NULL && !sev_es_setup_ghcb())) - sev_es_terminate(GHCB_SEV_ES_GEN_REQ); + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ); vc_ghcb_invalidate(boot_ghcb);
GHCB specification defines the reason code for reason set 0. The reason codes defined in the set 0 do not cover all possible causes for a guest to request termination. The reason set 1 to 255 is reserved for the vendor-specific codes. Reseve the reason set 1 for the Linux guest. Define an error codes for reason set 1. While at it, change the sev_es_terminate() to accept the reason set parameter. Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> --- arch/x86/boot/compressed/sev.c | 6 +++--- arch/x86/include/asm/sev-common.h | 8 ++++++++ arch/x86/kernel/sev-shared.c | 11 ++++------- arch/x86/kernel/sev.c | 4 ++-- 4 files changed, 17 insertions(+), 12 deletions(-)