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| author | Yang, Wei Y <wei.y.yang@intel.com> | 2011-08-09 18:14:01 +0800 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2011-09-25 19:18:02 +0300 |
| commit | cd46868c7f088baaaba8f81251c5929f6002d050 (patch) | |
| tree | 03cfc435d3d88e0546709bc69083f42cba7cd677 /arch/x86/kvm/paging_tmpl.h | |
| parent | e4e517b4be019787ada4cbbce2f04570c21b0cbd (diff) | |
| download | lwn-cd46868c7f088baaaba8f81251c5929f6002d050.tar.gz lwn-cd46868c7f088baaaba8f81251c5929f6002d050.zip | |
KVM: MMU: Fix SMEP failure during fetch
This patch fix kvm-unit-tests hanging and incorrect PT_ACCESSED_MASK
bit set in the case of SMEP fault. The code updated 'eperm' after
the variable was checked.
Signed-off-by: Yang, Wei <wei.y.yang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/kvm/paging_tmpl.h')
| -rw-r--r-- | arch/x86/kvm/paging_tmpl.h | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h index f6dd9feb201b..92994100638b 100644 --- a/arch/x86/kvm/paging_tmpl.h +++ b/arch/x86/kvm/paging_tmpl.h @@ -147,7 +147,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker, gfn_t table_gfn; unsigned index, pt_access, uninitialized_var(pte_access); gpa_t pte_gpa; - bool eperm; + bool eperm, last_gpte; int offset; const int write_fault = access & PFERR_WRITE_MASK; const int user_fault = access & PFERR_USER_MASK; @@ -221,6 +221,17 @@ retry_walk: eperm = true; #endif + last_gpte = FNAME(is_last_gpte)(walker, vcpu, mmu, pte); + if (last_gpte) { + pte_access = pt_access & + FNAME(gpte_access)(vcpu, pte, true); + /* check if the kernel is fetching from user page */ + if (unlikely(pte_access & PT_USER_MASK) && + kvm_read_cr4_bits(vcpu, X86_CR4_SMEP)) + if (fetch_fault && !user_fault) + eperm = true; + } + if (!eperm && unlikely(!(pte & PT_ACCESSED_MASK))) { int ret; trace_kvm_mmu_set_accessed_bit(table_gfn, index, @@ -238,18 +249,12 @@ retry_walk: walker->ptes[walker->level - 1] = pte; - if (FNAME(is_last_gpte)(walker, vcpu, mmu, pte)) { + if (last_gpte) { int lvl = walker->level; gpa_t real_gpa; gfn_t gfn; u32 ac; - /* check if the kernel is fetching from user page */ - if (unlikely(pte_access & PT_USER_MASK) && - kvm_read_cr4_bits(vcpu, X86_CR4_SMEP)) - if (fetch_fault && !user_fault) - eperm = true; - gfn = gpte_to_gfn_lvl(pte, lvl); gfn += (addr & PT_LVL_OFFSET_MASK(lvl)) >> PAGE_SHIFT; @@ -295,7 +300,6 @@ retry_walk: walker->ptes[walker->level - 1] = pte; } - pte_access = pt_access & FNAME(gpte_access)(vcpu, pte, true); walker->pt_access = pt_access; walker->pte_access = pte_access; pgprintk("%s: pte %llx pte_access %x pt_access %x\n", |