| Message ID | 20221214194056.161492-24-michael.roth@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support | expand |
On Wed, Dec 14, 2022 at 11:52 AM Michael Roth <michael.roth@amd.com> wrote: > > From: Brijesh Singh <brijesh.singh@amd.com> > > When SEV-SNP is enabled globally, a write from the host goes through the > RMP check. If the hardware encounters the check failure, then it raises > the #PF (with RMP set). Dump the RMP entry at the faulting pfn to help > the debug. > > Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> > Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> > Signed-off-by: Michael Roth <michael.roth@amd.com> > --- > arch/x86/include/asm/sev.h | 2 ++ > arch/x86/kernel/sev.c | 43 ++++++++++++++++++++++++++++++++++++++ > arch/x86/mm/fault.c | 7 ++++++- > 3 files changed, 51 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h > index 4eeedcaca593..2916f4150ac7 100644 > --- a/arch/x86/include/asm/sev.h > +++ b/arch/x86/include/asm/sev.h > @@ -215,6 +215,7 @@ int snp_lookup_rmpentry(u64 pfn, int *level); > int psmash(u64 pfn); > int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid, bool immutable); > int rmp_make_shared(u64 pfn, enum pg_level level); > +void sev_dump_rmpentry(u64 pfn); > #else > static inline void sev_es_ist_enter(struct pt_regs *regs) { } > static inline void sev_es_ist_exit(void) { } > @@ -247,6 +248,7 @@ static inline int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int as > return -ENODEV; > } > static inline int rmp_make_shared(u64 pfn, enum pg_level level) { return -ENODEV; } > +static inline void sev_dump_rmpentry(u64 pfn) {} > #endif > > #endif > diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c > index e2b38c3551be..1dd1b36bdfea 100644 > --- a/arch/x86/kernel/sev.c > +++ b/arch/x86/kernel/sev.c > @@ -2508,6 +2508,49 @@ static struct rmpentry *__snp_lookup_rmpentry(u64 pfn, int *level) > return entry; > } > > +void sev_dump_rmpentry(u64 pfn) > +{ > + unsigned long pfn_end; > + struct rmpentry *e; > + int level; > + > + e = __snp_lookup_rmpentry(pfn, &level); > + if (!e) { if (IS_ERR(e)) { > + pr_info("failed to read RMP entry pfn 0x%llx\n", pfn); > + return; > + } > + > + if (rmpentry_assigned(e)) { > + pr_info("RMPEntry paddr 0x%llx [assigned=%d immutable=%d pagesize=%d gpa=0x%lx" > + " asid=%d vmsa=%d validated=%d]\n", pfn << PAGE_SHIFT, > + rmpentry_assigned(e), e->info.immutable, rmpentry_pagesize(e), > + (unsigned long)e->info.gpa, e->info.asid, e->info.vmsa, > + e->info.validated); > + return; > + } > + > + /* > + * If the RMP entry at the faulting pfn was not assigned, then not sure > + * what caused the RMP violation. To get some useful debug information, > + * iterate through the entire 2MB region, and dump the RMP entries if > + * one of the bit in the RMP entry is set. > + */ > + pfn = pfn & ~(PTRS_PER_PMD - 1); > + pfn_end = pfn + PTRS_PER_PMD; > + > + while (pfn < pfn_end) { > + e = __snp_lookup_rmpentry(pfn, &level); > + if (!e) > + return; if (IS_ERR(e)) continue; > + > + if (e->low || e->high) > + pr_info("RMPEntry paddr 0x%llx: [high=0x%016llx low=0x%016llx]\n", > + pfn << PAGE_SHIFT, e->high, e->low); > + pfn++; > + } > +} > +EXPORT_SYMBOL_GPL(sev_dump_rmpentry); > + > /* > * Return 1 if the RMP entry is assigned, 0 if it exists but is not assigned, > * and -errno if there is no corresponding RMP entry. > diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c > index ded53879f98d..f2b16dcfbd9a 100644 > --- a/arch/x86/mm/fault.c > +++ b/arch/x86/mm/fault.c > @@ -536,6 +536,8 @@ static void show_ldttss(const struct desc_ptr *gdt, const char *name, u16 index) > static void > show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long address) > { > + unsigned long pfn; > + > if (!oops_may_print()) > return; > > @@ -608,7 +610,10 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long ad > show_ldttss(&gdt, "TR", tr); > } > > - dump_pagetable(address); > + pfn = dump_pagetable(address); > + > + if (error_code & X86_PF_RMP) > + sev_dump_rmpentry(pfn); > } > > static noinline void > -- > 2.25.1 >
On 1/13/2023 4:56 PM, Alper Gun wrote: > On Wed, Dec 14, 2022 at 11:52 AM Michael Roth <michael.roth@amd.com> wrote: >> >> From: Brijesh Singh <brijesh.singh@amd.com> >> >> When SEV-SNP is enabled globally, a write from the host goes through the >> RMP check. If the hardware encounters the check failure, then it raises >> the #PF (with RMP set). Dump the RMP entry at the faulting pfn to help >> the debug. >> >> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> >> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> >> Signed-off-by: Michael Roth <michael.roth@amd.com> >> --- >> arch/x86/include/asm/sev.h | 2 ++ >> arch/x86/kernel/sev.c | 43 ++++++++++++++++++++++++++++++++++++++ >> arch/x86/mm/fault.c | 7 ++++++- >> 3 files changed, 51 insertions(+), 1 deletion(-) >> >> diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h >> index 4eeedcaca593..2916f4150ac7 100644 >> --- a/arch/x86/include/asm/sev.h >> +++ b/arch/x86/include/asm/sev.h >> @@ -215,6 +215,7 @@ int snp_lookup_rmpentry(u64 pfn, int *level); >> int psmash(u64 pfn); >> int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid, bool immutable); >> int rmp_make_shared(u64 pfn, enum pg_level level); >> +void sev_dump_rmpentry(u64 pfn); >> #else >> static inline void sev_es_ist_enter(struct pt_regs *regs) { } >> static inline void sev_es_ist_exit(void) { } >> @@ -247,6 +248,7 @@ static inline int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int as >> return -ENODEV; >> } >> static inline int rmp_make_shared(u64 pfn, enum pg_level level) { return -ENODEV; } >> +static inline void sev_dump_rmpentry(u64 pfn) {} >> #endif >> >> #endif >> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c >> index e2b38c3551be..1dd1b36bdfea 100644 >> --- a/arch/x86/kernel/sev.c >> +++ b/arch/x86/kernel/sev.c >> @@ -2508,6 +2508,49 @@ static struct rmpentry *__snp_lookup_rmpentry(u64 pfn, int *level) >> return entry; >> } >> >> +void sev_dump_rmpentry(u64 pfn) >> +{ >> + unsigned long pfn_end; >> + struct rmpentry *e; >> + int level; >> + >> + e = __snp_lookup_rmpentry(pfn, &level); >> + if (!e) { > if (IS_ERR(e)) { > Yes, this needs to be fixed to IS_ERR(e) >> + pr_info("failed to read RMP entry pfn 0x%llx\n", pfn); >> + return; >> + } >> + >> + if (rmpentry_assigned(e)) { >> + pr_info("RMPEntry paddr 0x%llx [assigned=%d immutable=%d pagesize=%d gpa=0x%lx" >> + " asid=%d vmsa=%d validated=%d]\n", pfn << PAGE_SHIFT, >> + rmpentry_assigned(e), e->info.immutable, rmpentry_pagesize(e), >> + (unsigned long)e->info.gpa, e->info.asid, e->info.vmsa, >> + e->info.validated); >> + return; >> + } >> + >> + /* >> + * If the RMP entry at the faulting pfn was not assigned, then not sure >> + * what caused the RMP violation. To get some useful debug information, >> + * iterate through the entire 2MB region, and dump the RMP entries if >> + * one of the bit in the RMP entry is set. >> + */ >> + pfn = pfn & ~(PTRS_PER_PMD - 1); >> + pfn_end = pfn + PTRS_PER_PMD; >> + >> + while (pfn < pfn_end) { >> + e = __snp_lookup_rmpentry(pfn, &level); >> + if (!e) >> + return; > if (IS_ERR(e)) > continue; Again, this is correct, but then it should be : if (IS_ERR(e)) { pfn++; continue; } Thanks, Ashish >> + >> + if (e->low || e->high) >> + pr_info("RMPEntry paddr 0x%llx: [high=0x%016llx low=0x%016llx]\n", >> + pfn << PAGE_SHIFT, e->high, e->low); >> + pfn++; >> + } >> +} >> +EXPORT_SYMBOL_GPL(sev_dump_rmpentry); >> + >> /* >> * Return 1 if the RMP entry is assigned, 0 if it exists but is not assigned, >> * and -errno if there is no corresponding RMP entry. >> diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c >> index ded53879f98d..f2b16dcfbd9a 100644 >> --- a/arch/x86/mm/fault.c >> +++ b/arch/x86/mm/fault.c >> @@ -536,6 +536,8 @@ static void show_ldttss(const struct desc_ptr *gdt, const char *name, u16 index) >> static void >> show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long address) >> { >> + unsigned long pfn; >> + >> if (!oops_may_print()) >> return; >> >> @@ -608,7 +610,10 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long ad >> show_ldttss(&gdt, "TR", tr); >> } >> >> - dump_pagetable(address); >> + pfn = dump_pagetable(address); >> + >> + if (error_code & X86_PF_RMP) >> + sev_dump_rmpentry(pfn); >> } >> >> static noinline void >> -- >> 2.25.1 >>
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index 4eeedcaca593..2916f4150ac7 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -215,6 +215,7 @@ int snp_lookup_rmpentry(u64 pfn, int *level); int psmash(u64 pfn); int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int asid, bool immutable); int rmp_make_shared(u64 pfn, enum pg_level level); +void sev_dump_rmpentry(u64 pfn); #else static inline void sev_es_ist_enter(struct pt_regs *regs) { } static inline void sev_es_ist_exit(void) { } @@ -247,6 +248,7 @@ static inline int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, int as return -ENODEV; } static inline int rmp_make_shared(u64 pfn, enum pg_level level) { return -ENODEV; } +static inline void sev_dump_rmpentry(u64 pfn) {} #endif #endif diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index e2b38c3551be..1dd1b36bdfea 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -2508,6 +2508,49 @@ static struct rmpentry *__snp_lookup_rmpentry(u64 pfn, int *level) return entry; } +void sev_dump_rmpentry(u64 pfn) +{ + unsigned long pfn_end; + struct rmpentry *e; + int level; + + e = __snp_lookup_rmpentry(pfn, &level); + if (!e) { + pr_info("failed to read RMP entry pfn 0x%llx\n", pfn); + return; + } + + if (rmpentry_assigned(e)) { + pr_info("RMPEntry paddr 0x%llx [assigned=%d immutable=%d pagesize=%d gpa=0x%lx" + " asid=%d vmsa=%d validated=%d]\n", pfn << PAGE_SHIFT, + rmpentry_assigned(e), e->info.immutable, rmpentry_pagesize(e), + (unsigned long)e->info.gpa, e->info.asid, e->info.vmsa, + e->info.validated); + return; + } + + /* + * If the RMP entry at the faulting pfn was not assigned, then not sure + * what caused the RMP violation. To get some useful debug information, + * iterate through the entire 2MB region, and dump the RMP entries if + * one of the bit in the RMP entry is set. + */ + pfn = pfn & ~(PTRS_PER_PMD - 1); + pfn_end = pfn + PTRS_PER_PMD; + + while (pfn < pfn_end) { + e = __snp_lookup_rmpentry(pfn, &level); + if (!e) + return; + + if (e->low || e->high) + pr_info("RMPEntry paddr 0x%llx: [high=0x%016llx low=0x%016llx]\n", + pfn << PAGE_SHIFT, e->high, e->low); + pfn++; + } +} +EXPORT_SYMBOL_GPL(sev_dump_rmpentry); + /* * Return 1 if the RMP entry is assigned, 0 if it exists but is not assigned, * and -errno if there is no corresponding RMP entry. diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index ded53879f98d..f2b16dcfbd9a 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -536,6 +536,8 @@ static void show_ldttss(const struct desc_ptr *gdt, const char *name, u16 index) static void show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long address) { + unsigned long pfn; + if (!oops_may_print()) return; @@ -608,7 +610,10 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long ad show_ldttss(&gdt, "TR", tr); } - dump_pagetable(address); + pfn = dump_pagetable(address); + + if (error_code & X86_PF_RMP) + sev_dump_rmpentry(pfn); } static noinline void