Skip to content

Commit

Permalink
KVM: x86: fix access code passed to gva_to_gpa
Browse files Browse the repository at this point in the history 
The PK bit of the error code is computed dynamically in permission_fault
and therefore need not be passed to gva_to_gpa: only the access bits
(fetch, user, write) need to be passed down.

Not doing so causes a splat in the pku test:

   WARNING: CPU: 25 PID: 5465 at arch/x86/kvm/mmu.h:197 paging64_walk_addr_generic+0x594/0x750 [kvm]
   Hardware name: Intel Corporation WilsonCity/WilsonCity, BIOS WLYDCRB1.SYS.0014.D62.2001092233 01/09/2020
   RIP: 0010:paging64_walk_addr_generic+0x594/0x750 [kvm]
   Code: <0f> 0b e9 db fe ff ff 44 8b 43 04 4c 89 6c 24 30 8b 13 41 39 d0 89
   RSP: 0018:ff53778fc623fb60 EFLAGS: 00010202
   RAX: 0000000000000001 RBX: ff53778fc623fbf0 RCX: 0000000000000007
   RDX: 0000000000000001 RSI: 0000000000000002 RDI: ff4501efba818000
   RBP: 0000000000000020 R08: 0000000000000005 R09: 00000000004000e7
   R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000007
   R13: ff4501efba818388 R14: 10000000004000e7 R15: 0000000000000000
   FS:  00007f2dcf31a700(0000) GS:ff4501f1c8040000(0000) knlGS:0000000000000000
   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   CR2: 0000000000000000 CR3: 0000001dea475005 CR4: 0000000000763ee0
   DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
   DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
   PKRU: 55555554
   Call Trace:
    paging64_gva_to_gpa+0x3f/0xb0 [kvm]
    kvm_fixup_and_inject_pf_error+0x48/0xa0 [kvm]
    handle_exception_nmi+0x4fc/0x5b0 [kvm_intel]
    kvm_arch_vcpu_ioctl_run+0x911/0x1c10 [kvm]
    kvm_vcpu_ioctl+0x23e/0x5d0 [kvm]
    ksys_ioctl+0x92/0xb0
    __x64_sys_ioctl+0x16/0x20
    do_syscall_64+0x3e/0xb0
    entry_SYSCALL_64_after_hwframe+0x44/0xa9
   ---[ end trace d17eb998aee991da ]---

Reported-by: Sean Christopherson <[email protected]>
Fixes: 8978614 ("KVM: x86: Add helper functions for illegal GPA checking and page fault injection")
Signed-off-by: Paolo Bonzini <[email protected]>
  • Loading branch information
@bonzini
bonzini committed Aug 17, 2020
1 parent 98b0bf0 commit 19cf4b7
Showing 1 changed file with 3 additions and 1 deletion.
4 changes: 3 additions & 1 deletion arch/x86/kvm/x86.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -10743,9 +10743,11 @@ EXPORT_SYMBOL_GPL(kvm_spec_ctrl_test_value);
void kvm_fixup_and_inject_pf_error(struct kvm_vcpu *vcpu, gva_t gva, u16 error_code)
{
struct x86_exception fault;
u32 access = error_code &
(PFERR_WRITE_MASK | PFERR_FETCH_MASK | PFERR_USER_MASK);

if (!(error_code & PFERR_PRESENT_MASK) ||
vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, error_code, &fault) != UNMAPPED_GVA) {
vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, access, &fault) != UNMAPPED_GVA) {
/*
* If vcpu->arch.walk_mmu->gva_to_gpa succeeded, the page
* tables probably do not match the TLB. Just proceed
Expand Down

0 comments on commit 19cf4b7

Please sign in to comment.