Messages in this thread | | | From | Vitaly Kuznetsov <> | Subject | Re: [PATCH] kvm x86/mmu: use KVM_REQ_MMU_SYNC to sync when needed | Date | Mon, 31 Aug 2020 15:09:15 +0200 |
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Lai Jiangshan <jiangshanlai@gmail.com> writes:
> Ping @Sean Christopherson >
Let's try 'Beetlejuice' instead :-)
> On Mon, Aug 24, 2020 at 5:18 PM Lai Jiangshan <jiangshanlai@gmail.com> wrote: >> >> From: Lai Jiangshan <laijs@linux.alibaba.com> >> >> 8c8560b83390("KVM: x86/mmu: Use KVM_REQ_TLB_FLUSH_CURRENT for MMU specific flushes) >> changed it without giving any reason in the changelog. >> >> In theory, the syncing is needed, and need to be fixed by reverting >> this part of change.
Even if the original commit is not wordy enough this is hardly better. Are you seeing a particular scenario when a change in current vCPU's MMU requires flushing TLB entries for *other* contexts, ... (see below)
>> >> Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com> >> --- >> arch/x86/kvm/mmu/mmu.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c >> index 4e03841f053d..9a93de921f2b 100644 >> --- a/arch/x86/kvm/mmu/mmu.c >> +++ b/arch/x86/kvm/mmu/mmu.c >> @@ -2468,7 +2468,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, >> } >> >> if (sp->unsync_children) >> - kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu); >> + kvm_make_request(KVM_REQ_MMU_SYNC, vcpu);
... in particular, why are you reverting only this hunk? Please elaborate.
>> >> __clear_sp_write_flooding_count(sp); >> >> -- >> 2.19.1.6.gb485710b >> >
-- Vitaly
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