From: Sean Christopherson <seanjc@google.com>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
butt3rflyh4ck <butterflyhuangxx@gmail.com>,
kvm@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: KVM: Warn if mark_page_dirty() is called without an active vCPU
Date: Mon, 22 Nov 2021 17:01:59 +0000 [thread overview]
Message-ID: <YZvNB0ByFmdEkUVX@google.com> (raw)
In-Reply-To: <e8f40b8765f2feefb653d8a67e487818f66581aa.camel@infradead.org>
On Sat, Nov 20, 2021, David Woodhouse wrote:
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 6c5083f2eb50..72c6453bcef4 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -3020,12 +3020,17 @@ void mark_page_dirty_in_slot(struct kvm *kvm,
> struct kvm_memory_slot *memslot,
> gfn_t gfn)
> {
> + struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
> +
> + if (WARN_ON_ONCE(!vcpu) || WARN_ON_ONCE(vcpu->kvm != kvm))
Maybe use KVM_BUG_ON? And two separate WARNs are probably overkill.
if (KVM_BUG_ON(!vcpu || vcpu->kvm != kvm, kvm))
I'd also prefer to not retrieve the vCPU in the dirty_bitmap path, at least not
until it's necessary (for the proposed dirty quota throttling), though that's not
a strong preference.
> + return;
> +
> if (memslot && kvm_slot_dirty_track_enabled(memslot)) {
> unsigned long rel_gfn = gfn - memslot->base_gfn;
> u32 slot = (memslot->as_id << 16) | memslot->id;
>
> if (kvm->dirty_ring_size)
> - kvm_dirty_ring_push(kvm_dirty_ring_get(kvm),
> + kvm_dirty_ring_push(&vcpu->dirty_ring,
> slot, rel_gfn);
This can now squeeze on a single line.
kvm_dirty_ring_push(&vcpu->dirty_ring, slot, rel_gfn);
> else
> set_bit_le(rel_gfn, memslot->dirty_bitmap);
> --
> 2.31.1
>
next prev parent reply other threads:[~2021-11-22 17:02 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-18 17:14 There is a null-ptr-deref bug in kvm_dirty_ring_get in virt/kvm/dirty_ring.c butt3rflyh4ck
2021-10-21 20:08 ` Paolo Bonzini
2021-10-28 7:42 ` butt3rflyh4ck
2021-11-08 5:11 ` butt3rflyh4ck
2021-11-16 15:41 ` butt3rflyh4ck
2021-11-16 16:22 ` [EXTERNAL] " David Woodhouse
2021-11-16 17:07 ` David Woodhouse
2021-11-17 9:46 ` Woodhouse, David
2021-11-17 16:49 ` Paolo Bonzini
2021-11-17 18:10 ` Woodhouse, David
2021-11-20 10:16 ` KVM: Warn if mark_page_dirty() is called without an active vCPU David Woodhouse
2021-11-22 17:01 ` Sean Christopherson [this message]
2021-11-22 17:52 ` David Woodhouse
2021-11-22 18:49 ` Sean Christopherson
2022-01-13 12:06 ` Christian Borntraeger
2022-01-13 12:14 ` Paolo Bonzini
2022-01-13 12:29 ` [PATCH] KVM: avoid warning on s390 in mark_page_dirty Christian Borntraeger
2022-01-13 12:31 ` David Woodhouse
2022-01-18 8:37 ` Christian Borntraeger
2022-01-18 8:44 ` Paolo Bonzini
2022-01-18 8:53 ` Christian Borntraeger
2022-01-18 11:44 ` Paolo Bonzini
2022-01-13 12:30 ` KVM: Warn if mark_page_dirty() is called without an active vCPU David Woodhouse
2022-01-13 12:51 ` Christian Borntraeger
2022-01-13 13:22 ` David Woodhouse
2022-01-13 15:09 ` Christian Borntraeger
2022-01-13 14:36 ` Paolo Bonzini
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