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| author | Marcelo Tosatti <mtosatti@redhat.com> | 2013-03-12 22:36:43 -0300 |
|---|---|---|
| committer | Gleb Natapov <gleb@redhat.com> | 2013-03-13 11:46:09 +0200 |
| commit | 5d218814328da91a27e982748443e7e375e11396 (patch) | |
| tree | 46ef91eb8d845cea7500450fb041b9e5e444e63f /arch/x86/kvm/mmu.h | |
| parent | 57f252f22908535e04d520f3833a6e3116eb159d (diff) | |
| download | linux-stable-5d218814328da91a27e982748443e7e375e11396.tar.gz linux-stable-5d218814328da91a27e982748443e7e375e11396.tar.bz2 linux-stable-5d218814328da91a27e982748443e7e375e11396.zip | |
KVM: MMU: make kvm_mmu_available_pages robust against n_used_mmu_pages > n_max_mmu_pages
As noticed by Ulrich Obergfell <uobergfe@redhat.com>, the mmu
counters are for beancounting purposes only - so n_used_mmu_pages and
n_max_mmu_pages could be relaxed (example: before f0f5933a1626c8df7b),
resulting in n_used_mmu_pages > n_max_mmu_pages.
Make code robust against n_used_mmu_pages > n_max_mmu_pages.
Reviewed-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu.h')
| -rw-r--r-- | arch/x86/kvm/mmu.h | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index 69871080e866..3b1ad0049ea4 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -57,8 +57,11 @@ int kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context); static inline unsigned int kvm_mmu_available_pages(struct kvm *kvm) { - return kvm->arch.n_max_mmu_pages - - kvm->arch.n_used_mmu_pages; + if (kvm->arch.n_max_mmu_pages > kvm->arch.n_used_mmu_pages) + return kvm->arch.n_max_mmu_pages - + kvm->arch.n_used_mmu_pages; + + return 0; } static inline void kvm_mmu_free_some_pages(struct kvm_vcpu *vcpu) |