diff options
| author | Avi Kivity <avi@redhat.com> | 2010-03-15 13:59:57 +0200 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2010-05-17 12:15:43 +0300 |
| commit | 08e850c6536db302050c0287649e68e3bbdfe2c7 (patch) | |
| tree | 9eb7e554b53ea9eb1cb408f81234f404a43a54ab /arch/x86/include/asm/kvm_host.h | |
| parent | fbc5d139bb92e6822e4c000f97631a072d8babf9 (diff) | |
KVM: MMU: Reinstate pte prefetch on invlpg
Commit fb341f57 removed the pte prefetch on guest invlpg, citing guest races.
However, the SDM is adamant that prefetch is allowed:
"The processor may create entries in paging-structure caches for
translations required for prefetches and for accesses that are a
result of speculative execution that would never actually occur
in the executed code path."
And, in fact, there was a race in the prefetch code: we picked up the pte
without the mmu lock held, so an older invlpg could install the pte over
a newer invlpg.
Reinstate the prefetch logic, but this time note whether another invlpg has
executed using a counter. If a race occured, do not install the pte.
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch/x86/include/asm/kvm_host.h')
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index ea1b6c615f9f..28826c82d1e2 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -389,6 +389,7 @@ struct kvm_arch { unsigned int n_free_mmu_pages; unsigned int n_requested_mmu_pages; unsigned int n_alloc_mmu_pages; + atomic_t invlpg_counter; struct hlist_head mmu_page_hash[KVM_NUM_MMU_PAGES]; /* * Hash table of struct kvm_mmu_page. |