On 3/24/21 12:47 PM, Andy Lutomirski wrote: > On Wed, Mar 24, 2021 at 10:04 AM Brijesh Singh <brijesh.si...@amd.com> wrote: >> If hardware detects an RMP violation, it will raise a page-fault exception >> with the RMP bit set. To help the debug, dump the RMP entry of the faulting >> address. >> >> Cc: Thomas Gleixner <t...@linutronix.de> >> Cc: Ingo Molnar <mi...@redhat.com> >> Cc: Borislav Petkov <b...@alien8.de> >> Cc: Joerg Roedel <jroe...@suse.de> >> Cc: "H. Peter Anvin" <h...@zytor.com> >> Cc: Tony Luck <tony.l...@intel.com> >> Cc: Dave Hansen <dave.han...@intel.com> >> Cc: "Peter Zijlstra (Intel)" <pet...@infradead.org> >> Cc: Paolo Bonzini <pbonz...@redhat.com> >> Cc: Tom Lendacky <thomas.lenda...@amd.com> >> Cc: David Rientjes <rient...@google.com> >> Cc: Sean Christopherson <sea...@google.com> >> Cc: x...@kernel.org >> Cc: k...@vger.kernel.org >> Signed-off-by: Brijesh Singh <brijesh.si...@amd.com> >> --- >> arch/x86/mm/fault.c | 75 +++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 75 insertions(+) >> >> diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c >> index f39b551f89a6..7605e06a6dd9 100644 >> --- a/arch/x86/mm/fault.c >> +++ b/arch/x86/mm/fault.c >> @@ -31,6 +31,7 @@ >> #include <asm/pgtable_areas.h> /* VMALLOC_START, ... */ >> #include <asm/kvm_para.h> /* kvm_handle_async_pf */ >> #include <asm/vdso.h> /* fixup_vdso_exception() */ >> +#include <asm/sev-snp.h> /* lookup_rmpentry ... */ >> >> #define CREATE_TRACE_POINTS >> #include <asm/trace/exceptions.h> >> @@ -147,6 +148,76 @@ is_prefetch(struct pt_regs *regs, unsigned long >> error_code, unsigned long addr) >> DEFINE_SPINLOCK(pgd_lock); >> LIST_HEAD(pgd_list); >> >> +static void dump_rmpentry(struct page *page, rmpentry_t *e) >> +{ >> + unsigned long paddr = page_to_pfn(page) << PAGE_SHIFT; >> + >> + pr_alert("RMPEntry paddr 0x%lx [assigned=%d immutable=%d pagesize=%d >> gpa=0x%lx asid=%d " >> + "vmsa=%d validated=%d]\n", paddr, rmpentry_assigned(e), >> rmpentry_immutable(e), >> + rmpentry_pagesize(e), rmpentry_gpa(e), rmpentry_asid(e), >> rmpentry_vmsa(e), >> + rmpentry_validated(e)); >> + pr_alert("RMPEntry paddr 0x%lx %016llx %016llx\n", paddr, e->high, >> e->low); >> +} >> + >> +static void show_rmpentry(unsigned long address) >> +{ >> + struct page *page = virt_to_page(address); > This is an error path, and I don't think you have any particular > guarantee that virt_to_page(address) is valid. Please add appropriate > validation or use one of the slow lookup helpers.
Noted, thanks for the quick feedback.