Quote Gleb's mail:
| Back then kvm->lock protected memslot access so code like:
|
| mutex_lock(&vcpu->kvm->lock);
| kvm_mmu_zap_all(vcpu->kvm);
| mutex_unlock(&vcpu->kvm->lock);
|
| which is what 7aa81cc0 does was enough to guaranty that no vcpu will
| run while code is patched. This is no longer the case and
| mutex_lock(&vcpu->kvm->lock); is gone from that code path long time ago,
| so now kvm_mmu_zap_all() there is useless and the code is incorrect.
So we drop it and it will be fixed later
Signed-off-by: Xiao Guangrong <xiaoguangr...@linux.vnet.ibm.com>
---
arch/x86/kvm/x86.c | 7 -------
1 files changed, 0 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8d28810..6739b1d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5523,13 +5523,6 @@ static int emulator_fix_hypercall(struct
x86_emulate_ctxt *ctxt)
char instruction[3];
unsigned long rip = kvm_rip_read(vcpu);
- /*
- * Blow out the MMU to ensure that no other VCPU has an active mapping
- * to ensure that the updated hypercall appears atomically across all
- * VCPUs.
- */
- kvm_mmu_zap_all(vcpu->kvm);
-
kvm_x86_ops->patch_hypercall(vcpu, instruction);
return emulator_write_emulated(ctxt, rip, instruction, 3, NULL);
--
1.7.7.6
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