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authorSean Christopherson <sean.j.christopherson@intel.com>2019-02-05 13:01:12 -0800
committerPaolo Bonzini <pbonzini@redhat.com>2019-02-20 22:48:33 +0100
commite1359e2beb8b0a1188abc997273acbaedc8ee791 (patch)
tree6580d940b09ba1237ea00be4ddfe9fa09ebda312
parent152482580a1b0accb60676063a1ac57b2d12daf6 (diff)
downloadlinux-stericsson-e1359e2beb8b0a1188abc997273acbaedc8ee791.tar.gz
KVM: x86/mmu: Detect MMIO generation wrap in any address space
The check to detect a wrap of the MMIO generation explicitly looks for a generation number of zero. Now that unique memslots generation numbers are assigned to each address space, only address space 0 will get a generation number of exactly zero when wrapping. E.g. when address space 1 goes from 0x7fffe to 0x80002, the MMIO generation number will wrap to 0x2. Adjust the MMIO generation to strip the address space modifier prior to checking for a wrap. Fixes: 4bd518f1598d ("KVM: use separate generations for each address space") Cc: <stable@vger.kernel.org> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/x86/kvm/mmu.c21
1 files changed, 19 insertions, 2 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index a53a0e7ad9e6..c2f2c9de63ed 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -5895,11 +5895,28 @@ static bool kvm_has_zapped_obsolete_pages(struct kvm *kvm)
void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen)
{
+ gen &= MMIO_GEN_MASK;
+
+ /*
+ * Shift to eliminate the "update in-progress" flag, which isn't
+ * included in the spte's generation number.
+ */
+ gen >>= 1;
+
+ /*
+ * Generation numbers are incremented in multiples of the number of
+ * address spaces in order to provide unique generations across all
+ * address spaces. Strip what is effectively the address space
+ * modifier prior to checking for a wrap of the MMIO generation so
+ * that a wrap in any address space is detected.
+ */
+ gen &= ~((u64)KVM_ADDRESS_SPACE_NUM - 1);
+
/*
- * The very rare case: if the generation-number is round,
+ * The very rare case: if the MMIO generation number has wrapped,
* zap all shadow pages.
*/
- if (unlikely((gen & MMIO_GEN_MASK) == 0)) {
+ if (unlikely(gen == 0)) {
kvm_debug_ratelimited("kvm: zapping shadow pages for mmio generation wraparound\n");
kvm_mmu_invalidate_zap_all_pages(kvm);
}