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Message-ID: <CAOLK0pzrzydk9rk-Jijh=rA0oLkSafEqmumY2NSxe44J2=zv2A@mail.gmail.com>
Date: Mon, 15 Oct 2018 21:08:32 +0800
From: Tianyu Lan <lantianyu1986@...il.com>
To: Paolo Bonzini <pbonzini@...hat.com>
Cc: Tianyu Lan <Tianyu.Lan@...rosoft.com>, kys@...rosoft.com,
haiyangz@...rosoft.com, sthemmin@...rosoft.com,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>,
"the arch/x86 maintainers" <x86@...nel.org>,
Radim Krcmar <rkrcmar@...hat.com>,
devel@...uxdriverproject.org,
"linux-kernel@...r kernel org" <linux-kernel@...r.kernel.org>,
kvm <kvm@...r.kernel.org>, michael.h.kelley@...rosoft.com,
vkuznets@...hat.com
Subject: Re: [PATCH V4 7/15] KVM/MMU: Flush tlb directly in the kvm_zap_gfn_range()
Hi Paolo:
Thanks for your review.
On Mon, Oct 15, 2018 at 6:04 PM Paolo Bonzini <pbonzini@...hat.com> wrote:
>
> On 13/10/2018 16:53, lantianyu1986@...il.com wrote:
> > + bool flush = false;
> > int i;
> >
> > spin_lock(&kvm->mmu_lock);
> > @@ -5654,18 +5655,27 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
> > slots = __kvm_memslots(kvm, i);
> > kvm_for_each_memslot(memslot, slots) {
> > gfn_t start, end;
> > + bool flush_tlb = true;
> >
> > start = max(gfn_start, memslot->base_gfn);
> > end = min(gfn_end, memslot->base_gfn + memslot->npages);
> > if (start >= end)
> > continue;
> >
> > - slot_handle_level_range(kvm, memslot, kvm_zap_rmapp,
> > - PT_PAGE_TABLE_LEVEL, PT_MAX_HUGEPAGE_LEVEL,
> > - start, end - 1, true);
> > + if (kvm_available_flush_tlb_with_range())
> > + flush_tlb = false;
>
> This should be moved outside the for, because it's invariant.
>
> > + flush = slot_handle_level_range(kvm, memslot,
> > + kvm_zap_rmapp, PT_PAGE_TABLE_LEVEL,
> > + PT_MAX_HUGEPAGE_LEVEL, start,
> > + end - 1, flush_tlb);
>
> ... and this should be "flush |= ".
> > }
> > }
> >
> > + if (flush && kvm_available_flush_tlb_with_range())
> > + kvm_flush_remote_tlbs_with_address(kvm, gfn_start,
> > + gfn_end - gfn_start + 1);
> > +
>
> ... and this can be just if (flush), because if flush_tlb is true then
> slot_handle_level_range always returns false.
OK. Will update.
--
Best regards
Tianyu Lan
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