| Message ID | af381cc88410c0e2c48fda5732741edd0d7609ac.1655761627.git.ashish.kalra@amd.com |
|---|---|
| State | New |
| Headers | show |
| Series | Add AMD Secure Nested Paging (SEV-SNP) | expand |
On Mon, Jun 20, 2022 at 11:03:58PM +0000, Ashish Kalra 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> > --- > arch/x86/include/asm/sev.h | 7 +++++++ > arch/x86/kernel/sev.c | 43 ++++++++++++++++++++++++++++++++++++++ > arch/x86/mm/fault.c | 17 +++++++++++---- > include/linux/sev.h | 2 ++ > 4 files changed, 65 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h > index 6ab872311544..c0c4df817159 100644 > --- a/arch/x86/include/asm/sev.h > +++ b/arch/x86/include/asm/sev.h > @@ -113,6 +113,11 @@ struct __packed rmpentry { > > #define rmpentry_assigned(x) ((x)->info.assigned) > #define rmpentry_pagesize(x) ((x)->info.pagesize) > +#define rmpentry_vmsa(x) ((x)->info.vmsa) > +#define rmpentry_asid(x) ((x)->info.asid) > +#define rmpentry_validated(x) ((x)->info.validated) > +#define rmpentry_gpa(x) ((unsigned long)(x)->info.gpa) > +#define rmpentry_immutable(x) ((x)->info.immutable) > > #define RMPADJUST_VMSA_PAGE_BIT BIT(16) > > @@ -205,6 +210,7 @@ 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); > +void dump_rmpentry(u64 pfn); > #else > static inline void sev_es_ist_enter(struct pt_regs *regs) { } > static inline void sev_es_ist_exit(void) { } > @@ -229,6 +235,7 @@ static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *in > { > return -ENOTTY; > } > +static inline void dump_rmpentry(u64 pfn) {} > #endif > > #endif > diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c > index 734cddd837f5..6640a639fffc 100644 > --- a/arch/x86/kernel/sev.c > +++ b/arch/x86/kernel/sev.c > @@ -2414,6 +2414,49 @@ static struct rmpentry *__snp_lookup_rmpentry(u64 pfn, int *level) > return entry; > } > > +void dump_rmpentry(u64 pfn) > +{ > + unsigned long pfn_end; > + struct rmpentry *e; > + int level; > + > + e = __snp_lookup_rmpentry(pfn, &level); > + if (!e) { __snp_lookup_rmpentry may return -errno so this should be: if (e != 1) > + pr_alert("failed to read RMP entry pfn 0x%llx\n", pfn); > + return; > + } > + > + if (rmpentry_assigned(e)) { > + pr_alert("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), rmpentry_immutable(e), rmpentry_pagesize(e), > + rmpentry_gpa(e), rmpentry_asid(e), rmpentry_vmsa(e), > + rmpentry_validated(e)); > + return; > + } > + > + /* > + * If the RMP entry at the faulting pfn was not assigned, then we do not > + * know what caused the RMP violation. To get some useful debug information, > + * let 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) if (e != 1) > + return; > + > + if (e->low || e->high) > + pr_alert("RMPEntry paddr 0x%llx: [high=0x%016llx low=0x%016llx]\n", > + pfn << PAGE_SHIFT, e->high, e->low); > + pfn++; > + } > +} > +EXPORT_SYMBOL_GPL(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 f5de9673093a..25896a6ba04a 100644 > --- a/arch/x86/mm/fault.c > +++ b/arch/x86/mm/fault.c > @@ -34,6 +34,7 @@ > #include <asm/kvm_para.h> /* kvm_handle_async_pf */ > #include <asm/vdso.h> /* fixup_vdso_exception() */ > #include <asm/irq_stack.h> > +#include <asm/sev.h> /* dump_rmpentry() */ > > #define CREATE_TRACE_POINTS > #include <asm/trace/exceptions.h> > @@ -290,7 +291,7 @@ static bool low_pfn(unsigned long pfn) > return pfn < max_low_pfn; > } > > -static void dump_pagetable(unsigned long address) > +static void dump_pagetable(unsigned long address, bool show_rmpentry) > { > pgd_t *base = __va(read_cr3_pa()); > pgd_t *pgd = &base[pgd_index(address)]; > @@ -346,10 +347,11 @@ static int bad_address(void *p) > return get_kernel_nofault(dummy, (unsigned long *)p); > } > > -static void dump_pagetable(unsigned long address) > +static void dump_pagetable(unsigned long address, bool show_rmpentry) > { > pgd_t *base = __va(read_cr3_pa()); > pgd_t *pgd = base + pgd_index(address); > + unsigned long pfn; > p4d_t *p4d; > pud_t *pud; > pmd_t *pmd; > @@ -367,6 +369,7 @@ static void dump_pagetable(unsigned long address) > if (bad_address(p4d)) > goto bad; > > + pfn = p4d_pfn(*p4d); > pr_cont("P4D %lx ", p4d_val(*p4d)); > if (!p4d_present(*p4d) || p4d_large(*p4d)) > goto out; > @@ -375,6 +378,7 @@ static void dump_pagetable(unsigned long address) > if (bad_address(pud)) > goto bad; > > + pfn = pud_pfn(*pud); > pr_cont("PUD %lx ", pud_val(*pud)); > if (!pud_present(*pud) || pud_large(*pud)) > goto out; > @@ -383,6 +387,7 @@ static void dump_pagetable(unsigned long address) > if (bad_address(pmd)) > goto bad; > > + pfn = pmd_pfn(*pmd); > pr_cont("PMD %lx ", pmd_val(*pmd)); > if (!pmd_present(*pmd) || pmd_large(*pmd)) > goto out; > @@ -391,9 +396,13 @@ static void dump_pagetable(unsigned long address) > if (bad_address(pte)) > goto bad; > > + pfn = pte_pfn(*pte); > pr_cont("PTE %lx", pte_val(*pte)); > out: > pr_cont("\n"); > + > + if (show_rmpentry) > + dump_rmpentry(pfn); > return; > bad: > pr_info("BAD\n"); > @@ -579,7 +588,7 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long ad > show_ldttss(&gdt, "TR", tr); > } > > - dump_pagetable(address); > + dump_pagetable(address, error_code & X86_PF_RMP); > } > > static noinline void > @@ -596,7 +605,7 @@ pgtable_bad(struct pt_regs *regs, unsigned long error_code, > > printk(KERN_ALERT "%s: Corrupted page table at address %lx\n", > tsk->comm, address); > - dump_pagetable(address); > + dump_pagetable(address, false); > > if (__die("Bad pagetable", regs, error_code)) > sig = 0; > diff --git a/include/linux/sev.h b/include/linux/sev.h > index 1a68842789e1..734b13a69c54 100644 > --- a/include/linux/sev.h > +++ b/include/linux/sev.h > @@ -16,6 +16,7 @@ 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 dump_rmpentry(u64 pfn); > #else > static inline int snp_lookup_rmpentry(u64 pfn, int *level) { return 0; } > static inline int psmash(u64 pfn) { return -ENXIO; } > @@ -25,6 +26,7 @@ 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 dump_rmpentry(u64 pfn) { } > > #endif /* CONFIG_AMD_MEM_ENCRYPT */ > #endif /* __LINUX_SEV_H */ > -- > 2.25.1 >
On Wed, Jun 22, 2022 at 04:33:04PM +0200, Jeremi Piotrowski wrote: > On Mon, Jun 20, 2022 at 11:03:58PM +0000, Ashish Kalra 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> > > --- > > arch/x86/include/asm/sev.h | 7 +++++++ > > arch/x86/kernel/sev.c | 43 ++++++++++++++++++++++++++++++++++++++ > > arch/x86/mm/fault.c | 17 +++++++++++---- > > include/linux/sev.h | 2 ++ > > 4 files changed, 65 insertions(+), 4 deletions(-) > > > > diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h > > index 6ab872311544..c0c4df817159 100644 > > --- a/arch/x86/include/asm/sev.h > > +++ b/arch/x86/include/asm/sev.h > > @@ -113,6 +113,11 @@ struct __packed rmpentry { > > > > #define rmpentry_assigned(x) ((x)->info.assigned) > > #define rmpentry_pagesize(x) ((x)->info.pagesize) > > +#define rmpentry_vmsa(x) ((x)->info.vmsa) > > +#define rmpentry_asid(x) ((x)->info.asid) > > +#define rmpentry_validated(x) ((x)->info.validated) > > +#define rmpentry_gpa(x) ((unsigned long)(x)->info.gpa) > > +#define rmpentry_immutable(x) ((x)->info.immutable) > > > > #define RMPADJUST_VMSA_PAGE_BIT BIT(16) > > > > @@ -205,6 +210,7 @@ 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); > > +void dump_rmpentry(u64 pfn); > > #else > > static inline void sev_es_ist_enter(struct pt_regs *regs) { } > > static inline void sev_es_ist_exit(void) { } > > @@ -229,6 +235,7 @@ static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *in > > { > > return -ENOTTY; > > } > > +static inline void dump_rmpentry(u64 pfn) {} > > #endif > > > > #endif > > diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c > > index 734cddd837f5..6640a639fffc 100644 > > --- a/arch/x86/kernel/sev.c > > +++ b/arch/x86/kernel/sev.c > > @@ -2414,6 +2414,49 @@ static struct rmpentry *__snp_lookup_rmpentry(u64 pfn, int *level) > > return entry; > > } > > > > +void dump_rmpentry(u64 pfn) > > +{ > > + unsigned long pfn_end; > > + struct rmpentry *e; > > + int level; > > + > > + e = __snp_lookup_rmpentry(pfn, &level); > > + if (!e) { > > __snp_lookup_rmpentry may return -errno so this should be: > > if (e != 1) Sorry, actually it should be: if (IS_ERR_OR_NULL(e)) { > > > + pr_alert("failed to read RMP entry pfn 0x%llx\n", pfn); > > + return; > > + } > > + > > + if (rmpentry_assigned(e)) { > > + pr_alert("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), rmpentry_immutable(e), rmpentry_pagesize(e), > > + rmpentry_gpa(e), rmpentry_asid(e), rmpentry_vmsa(e), > > + rmpentry_validated(e)); > > + return; > > + } > > + > > + /* > > + * If the RMP entry at the faulting pfn was not assigned, then we do not > > + * know what caused the RMP violation. To get some useful debug information, > > + * let 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) > > if (e != 1) > and this too: if (IS_ERR_OR_NULL(e)) > > + return; > > + > > + if (e->low || e->high) > > + pr_alert("RMPEntry paddr 0x%llx: [high=0x%016llx low=0x%016llx]\n", > > + pfn << PAGE_SHIFT, e->high, e->low); > > + pfn++; > > + } > > +} > > +EXPORT_SYMBOL_GPL(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 f5de9673093a..25896a6ba04a 100644 > > --- a/arch/x86/mm/fault.c > > +++ b/arch/x86/mm/fault.c > > @@ -34,6 +34,7 @@ > > #include <asm/kvm_para.h> /* kvm_handle_async_pf */ > > #include <asm/vdso.h> /* fixup_vdso_exception() */ > > #include <asm/irq_stack.h> > > +#include <asm/sev.h> /* dump_rmpentry() */ > > > > #define CREATE_TRACE_POINTS > > #include <asm/trace/exceptions.h> > > @@ -290,7 +291,7 @@ static bool low_pfn(unsigned long pfn) > > return pfn < max_low_pfn; > > } > > > > -static void dump_pagetable(unsigned long address) > > +static void dump_pagetable(unsigned long address, bool show_rmpentry) > > { > > pgd_t *base = __va(read_cr3_pa()); > > pgd_t *pgd = &base[pgd_index(address)]; > > @@ -346,10 +347,11 @@ static int bad_address(void *p) > > return get_kernel_nofault(dummy, (unsigned long *)p); > > } > > > > -static void dump_pagetable(unsigned long address) > > +static void dump_pagetable(unsigned long address, bool show_rmpentry) > > { > > pgd_t *base = __va(read_cr3_pa()); > > pgd_t *pgd = base + pgd_index(address); > > + unsigned long pfn; > > p4d_t *p4d; > > pud_t *pud; > > pmd_t *pmd; > > @@ -367,6 +369,7 @@ static void dump_pagetable(unsigned long address) > > if (bad_address(p4d)) > > goto bad; > > > > + pfn = p4d_pfn(*p4d); > > pr_cont("P4D %lx ", p4d_val(*p4d)); > > if (!p4d_present(*p4d) || p4d_large(*p4d)) > > goto out; > > @@ -375,6 +378,7 @@ static void dump_pagetable(unsigned long address) > > if (bad_address(pud)) > > goto bad; > > > > + pfn = pud_pfn(*pud); > > pr_cont("PUD %lx ", pud_val(*pud)); > > if (!pud_present(*pud) || pud_large(*pud)) > > goto out; > > @@ -383,6 +387,7 @@ static void dump_pagetable(unsigned long address) > > if (bad_address(pmd)) > > goto bad; > > > > + pfn = pmd_pfn(*pmd); > > pr_cont("PMD %lx ", pmd_val(*pmd)); > > if (!pmd_present(*pmd) || pmd_large(*pmd)) > > goto out; > > @@ -391,9 +396,13 @@ static void dump_pagetable(unsigned long address) > > if (bad_address(pte)) > > goto bad; > > > > + pfn = pte_pfn(*pte); > > pr_cont("PTE %lx", pte_val(*pte)); > > out: > > pr_cont("\n"); > > + > > + if (show_rmpentry) > > + dump_rmpentry(pfn); > > return; > > bad: > > pr_info("BAD\n"); > > @@ -579,7 +588,7 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long ad > > show_ldttss(&gdt, "TR", tr); > > } > > > > - dump_pagetable(address); > > + dump_pagetable(address, error_code & X86_PF_RMP); > > } > > > > static noinline void > > @@ -596,7 +605,7 @@ pgtable_bad(struct pt_regs *regs, unsigned long error_code, > > > > printk(KERN_ALERT "%s: Corrupted page table at address %lx\n", > > tsk->comm, address); > > - dump_pagetable(address); > > + dump_pagetable(address, false); > > > > if (__die("Bad pagetable", regs, error_code)) > > sig = 0; > > diff --git a/include/linux/sev.h b/include/linux/sev.h > > index 1a68842789e1..734b13a69c54 100644 > > --- a/include/linux/sev.h > > +++ b/include/linux/sev.h > > @@ -16,6 +16,7 @@ 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 dump_rmpentry(u64 pfn); > > #else > > static inline int snp_lookup_rmpentry(u64 pfn, int *level) { return 0; } > > static inline int psmash(u64 pfn) { return -ENXIO; } > > @@ -25,6 +26,7 @@ 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 dump_rmpentry(u64 pfn) { } > > > > #endif /* CONFIG_AMD_MEM_ENCRYPT */ > > #endif /* __LINUX_SEV_H */ > > -- > > 2.25.1 > >
[AMD Official Use Only - General] >> > +void dump_rmpentry(u64 pfn) >> > +{ >> > + unsigned long pfn_end; >> > + struct rmpentry *e; >> > + int level; >> > + >> > + e = __snp_lookup_rmpentry(pfn, &level); >> > + if (!e) { >> >> __snp_lookup_rmpentry may return -errno so this should be: >> >> if (e != 1) >Sorry, actually it should be: > if (IS_ERR_OR_NULL(e)) { I will fix this accordingly. >> > + >> > + while (pfn < pfn_end) { >> > + e = __snp_lookup_rmpentry(pfn, &level); >> > + if (!e) >> >> if (e != 1) >> >and this too: > if (IS_ERR_OR_NULL(e)) Same here. Thanks, Ashish
On Mon, Jun 20, 2022 at 11:03:58PM +0000, Ashish Kalra 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> > --- > arch/x86/include/asm/sev.h | 7 +++++++ > arch/x86/kernel/sev.c | 43 ++++++++++++++++++++++++++++++++++++++ > arch/x86/mm/fault.c | 17 +++++++++++---- > include/linux/sev.h | 2 ++ > 4 files changed, 65 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h > index 6ab872311544..c0c4df817159 100644 > --- a/arch/x86/include/asm/sev.h > +++ b/arch/x86/include/asm/sev.h > @@ -113,6 +113,11 @@ struct __packed rmpentry { > > #define rmpentry_assigned(x) ((x)->info.assigned) > #define rmpentry_pagesize(x) ((x)->info.pagesize) > +#define rmpentry_vmsa(x) ((x)->info.vmsa) > +#define rmpentry_asid(x) ((x)->info.asid) > +#define rmpentry_validated(x) ((x)->info.validated) > +#define rmpentry_gpa(x) ((unsigned long)(x)->info.gpa) > +#define rmpentry_immutable(x) ((x)->info.immutable) If you're going to do that, use inline functions pls so that it checks the argument at least. Also, add such functions only when they're called multiple times - no need to add one for every field if you're going to access that field only once in the whole kernel. > > #define RMPADJUST_VMSA_PAGE_BIT BIT(16) > > @@ -205,6 +210,7 @@ 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); > +void dump_rmpentry(u64 pfn); > #else > static inline void sev_es_ist_enter(struct pt_regs *regs) { } > static inline void sev_es_ist_exit(void) { } > @@ -229,6 +235,7 @@ static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *in > { > return -ENOTTY; > } > +static inline void dump_rmpentry(u64 pfn) {} > #endif > > #endif > diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c > index 734cddd837f5..6640a639fffc 100644 > --- a/arch/x86/kernel/sev.c > +++ b/arch/x86/kernel/sev.c > @@ -2414,6 +2414,49 @@ static struct rmpentry *__snp_lookup_rmpentry(u64 pfn, int *level) > return entry; > } > > +void dump_rmpentry(u64 pfn) External function - it better belong to a namespace: sev_dump_rmpentry() > +{ > + unsigned long pfn_end; > + struct rmpentry *e; > + int level; > + > + e = __snp_lookup_rmpentry(pfn, &level); > + if (!e) { > + pr_alert("failed to read RMP entry pfn 0x%llx\n", pfn); Why alert? Dumping stuff is either pr_debug or pr_info... > + return; > + } > + > + if (rmpentry_assigned(e)) { > + pr_alert("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), rmpentry_immutable(e), rmpentry_pagesize(e), > + rmpentry_gpa(e), rmpentry_asid(e), rmpentry_vmsa(e), > + rmpentry_validated(e)); > + return; > + } > + > + /* > + * If the RMP entry at the faulting pfn was not assigned, then we do not Who's "we"? > + * know what caused the RMP violation. To get some useful debug information, > + * let 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) This is going to confuse people because they're going to miss a zero entry. Just dump the whole thing. ... > @@ -579,7 +588,7 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long ad > show_ldttss(&gdt, "TR", tr); > } > > - dump_pagetable(address); > + dump_pagetable(address, error_code & X86_PF_RMP); Eww. I'd prefer to see pfn = dump_pagetable(address); if (error_code & X86_PF_RMP) sev_dump_rmpentry(pfn); instead of passing around this SEV-specific arg in generic x86 fault code. The change to return the pfn from dump_pagetable() should be a pre-patch ofc. Thx.
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index 6ab872311544..c0c4df817159 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -113,6 +113,11 @@ struct __packed rmpentry { #define rmpentry_assigned(x) ((x)->info.assigned) #define rmpentry_pagesize(x) ((x)->info.pagesize) +#define rmpentry_vmsa(x) ((x)->info.vmsa) +#define rmpentry_asid(x) ((x)->info.asid) +#define rmpentry_validated(x) ((x)->info.validated) +#define rmpentry_gpa(x) ((unsigned long)(x)->info.gpa) +#define rmpentry_immutable(x) ((x)->info.immutable) #define RMPADJUST_VMSA_PAGE_BIT BIT(16) @@ -205,6 +210,7 @@ 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); +void dump_rmpentry(u64 pfn); #else static inline void sev_es_ist_enter(struct pt_regs *regs) { } static inline void sev_es_ist_exit(void) { } @@ -229,6 +235,7 @@ static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *in { return -ENOTTY; } +static inline void dump_rmpentry(u64 pfn) {} #endif #endif diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 734cddd837f5..6640a639fffc 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -2414,6 +2414,49 @@ static struct rmpentry *__snp_lookup_rmpentry(u64 pfn, int *level) return entry; } +void dump_rmpentry(u64 pfn) +{ + unsigned long pfn_end; + struct rmpentry *e; + int level; + + e = __snp_lookup_rmpentry(pfn, &level); + if (!e) { + pr_alert("failed to read RMP entry pfn 0x%llx\n", pfn); + return; + } + + if (rmpentry_assigned(e)) { + pr_alert("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), rmpentry_immutable(e), rmpentry_pagesize(e), + rmpentry_gpa(e), rmpentry_asid(e), rmpentry_vmsa(e), + rmpentry_validated(e)); + return; + } + + /* + * If the RMP entry at the faulting pfn was not assigned, then we do not + * know what caused the RMP violation. To get some useful debug information, + * let 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_alert("RMPEntry paddr 0x%llx: [high=0x%016llx low=0x%016llx]\n", + pfn << PAGE_SHIFT, e->high, e->low); + pfn++; + } +} +EXPORT_SYMBOL_GPL(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 f5de9673093a..25896a6ba04a 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -34,6 +34,7 @@ #include <asm/kvm_para.h> /* kvm_handle_async_pf */ #include <asm/vdso.h> /* fixup_vdso_exception() */ #include <asm/irq_stack.h> +#include <asm/sev.h> /* dump_rmpentry() */ #define CREATE_TRACE_POINTS #include <asm/trace/exceptions.h> @@ -290,7 +291,7 @@ static bool low_pfn(unsigned long pfn) return pfn < max_low_pfn; } -static void dump_pagetable(unsigned long address) +static void dump_pagetable(unsigned long address, bool show_rmpentry) { pgd_t *base = __va(read_cr3_pa()); pgd_t *pgd = &base[pgd_index(address)]; @@ -346,10 +347,11 @@ static int bad_address(void *p) return get_kernel_nofault(dummy, (unsigned long *)p); } -static void dump_pagetable(unsigned long address) +static void dump_pagetable(unsigned long address, bool show_rmpentry) { pgd_t *base = __va(read_cr3_pa()); pgd_t *pgd = base + pgd_index(address); + unsigned long pfn; p4d_t *p4d; pud_t *pud; pmd_t *pmd; @@ -367,6 +369,7 @@ static void dump_pagetable(unsigned long address) if (bad_address(p4d)) goto bad; + pfn = p4d_pfn(*p4d); pr_cont("P4D %lx ", p4d_val(*p4d)); if (!p4d_present(*p4d) || p4d_large(*p4d)) goto out; @@ -375,6 +378,7 @@ static void dump_pagetable(unsigned long address) if (bad_address(pud)) goto bad; + pfn = pud_pfn(*pud); pr_cont("PUD %lx ", pud_val(*pud)); if (!pud_present(*pud) || pud_large(*pud)) goto out; @@ -383,6 +387,7 @@ static void dump_pagetable(unsigned long address) if (bad_address(pmd)) goto bad; + pfn = pmd_pfn(*pmd); pr_cont("PMD %lx ", pmd_val(*pmd)); if (!pmd_present(*pmd) || pmd_large(*pmd)) goto out; @@ -391,9 +396,13 @@ static void dump_pagetable(unsigned long address) if (bad_address(pte)) goto bad; + pfn = pte_pfn(*pte); pr_cont("PTE %lx", pte_val(*pte)); out: pr_cont("\n"); + + if (show_rmpentry) + dump_rmpentry(pfn); return; bad: pr_info("BAD\n"); @@ -579,7 +588,7 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long ad show_ldttss(&gdt, "TR", tr); } - dump_pagetable(address); + dump_pagetable(address, error_code & X86_PF_RMP); } static noinline void @@ -596,7 +605,7 @@ pgtable_bad(struct pt_regs *regs, unsigned long error_code, printk(KERN_ALERT "%s: Corrupted page table at address %lx\n", tsk->comm, address); - dump_pagetable(address); + dump_pagetable(address, false); if (__die("Bad pagetable", regs, error_code)) sig = 0; diff --git a/include/linux/sev.h b/include/linux/sev.h index 1a68842789e1..734b13a69c54 100644 --- a/include/linux/sev.h +++ b/include/linux/sev.h @@ -16,6 +16,7 @@ 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 dump_rmpentry(u64 pfn); #else static inline int snp_lookup_rmpentry(u64 pfn, int *level) { return 0; } static inline int psmash(u64 pfn) { return -ENXIO; } @@ -25,6 +26,7 @@ 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 dump_rmpentry(u64 pfn) { } #endif /* CONFIG_AMD_MEM_ENCRYPT */ #endif /* __LINUX_SEV_H */