diff options
| author | Avi Kivity <avi@qumranet.com> | 2008-07-23 11:43:43 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-08-01 12:43:00 -0700 |
| commit | 8c5a4a12d8d5bf025a09a576a0b5c62e0167423c (patch) | |
| tree | 098f64ebd822ff4b09df7a563f12a5be624ea8f7 | |
| parent | c857ebba6025350232c87d89e459338f139a50ab (diff) | |
KVM: MMU: Fix potential race setting upper shadow ptes on nonpae hosts
Original-Commit-Hash: c23a6fe17abf8562e675465f8d55ba1a551d314d
The direct mapped shadow code (used for real mode and two dimensional paging)
sets upper-level ptes using direct assignment rather than calling
set_shadow_pte(). A nonpae host will split this into two writes, which opens
up a race if another vcpu accesses the same memory area.
Fix by calling set_shadow_pte() instead of assigning directly.
Noticed by Izik Eidus.
Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | arch/x86/kvm/mmu.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index c640b2f96c86..c26d811d9191 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1171,9 +1171,10 @@ static int __direct_map(struct kvm_vcpu *vcpu, gpa_t v, int write, return -ENOMEM; } - table[index] = __pa(new_table->spt) - | PT_PRESENT_MASK | PT_WRITABLE_MASK - | shadow_user_mask | shadow_x_mask; + set_shadow_pte(&table[index], + __pa(new_table->spt) + | PT_PRESENT_MASK | PT_WRITABLE_MASK + | shadow_user_mask | shadow_x_mask); } table_addr = table[index] & PT64_BASE_ADDR_MASK; } |