This information will be useful for debugging things like page faults
due to RMP access violations and RMPUPDATE failures.
Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>
[mdr: move helper to standalone patch]
Signed-off-by: Michael Roth <michael.roth@xxxxxxx>
---
arch/x86/include/asm/sev.h | 2 ++
arch/x86/kernel/sev.c | 48 ++++++++++++++++++++++++++++++++++++++
2 files changed, 50 insertions(+)
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 8d3ce2ad27da..edbb7fa488af 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -198,6 +198,7 @@ bool snp_init(struct boot_params *bp);
void __init __noreturn snp_abort(void);
int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, unsigned long *fw_err);
int snp_lookup_rmpentry(u64 pfn, int *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) { }
@@ -223,6 +224,7 @@ static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *in
return -ENOTTY;
}
static inline int snp_lookup_rmpentry(u64 pfn, int *level) { return 0; }
+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 a063c1b98034..a01741c4a1b8 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -2504,6 +2504,54 @@ 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 (IS_ERR(e)) {
+ pr_info("Failed to read RMP entry for 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);
+
+ /* Dump all the non-zero entries if debug enabled */
+ if (!sev_cfg.debug)
+ 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 (IS_ERR(e)) {
+ pr_info("Failed to read RMP entry for PFN 0x%llx\n", pfn);
+ pfn++;
+ 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.
--
2.25.1
