Messages in this thread | | | Subject | Re: [PATCH 3/4] KVM: X86: Use smp_rmb() to pair with smp_wmb() in mmu_try_to_unsync_pages() | From | Lai Jiangshan <> | Date | Thu, 21 Oct 2021 10:32:30 +0800 |
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Hello Junaid Shahid
Any comments on the patch? I may have been misunderstanding many things and I have been often.
thanks Lai
On 2021/10/19 19:01, Lai Jiangshan wrote: > From: Lai Jiangshan <laijs@linux.alibaba.com> > > The commit 578e1c4db2213 ("kvm: x86: Avoid taking MMU lock in > kvm_mmu_sync_roots if no sync is needed") added smp_wmb() in > mmu_try_to_unsync_pages(), but the corresponding smp_load_acquire() > isn't used on the load of SPTE.W which is impossible since the load of > SPTE.W is performed in the CPU's pagetable walking. > > This patch changes to use smp_rmb() instead. This patch fixes nothing > but just comments since smp_rmb() is NOP and compiler barrier() is not > required since the load of SPTE.W is before VMEXIT. > > Cc: Junaid Shahid <junaids@google.com> > Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
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