From: Peter Xu <peterx@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Dr David Alan Gilbert <dgilbert@redhat.com>,
Christophe de Dinechin <dinechin@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
"Michael S . Tsirkin" <mst@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>
Subject: Re: [PATCH RESEND v2 15/17] KVM: selftests: Add dirty ring buffer test
Date: Tue, 24 Dec 2019 10:22:45 -0500 [thread overview]
Message-ID: <20191224152245.GA17176@xz-x1> (raw)
In-Reply-To: <521fcdf6-db45-566d-7a83-e8c7a22cf7c5@redhat.com>
On Tue, Dec 24, 2019 at 02:18:37PM +0800, Jason Wang wrote:
[...]
> > + while (fetch != avail) {
> > + cur = &dirty_gfns[fetch % TEST_DIRTY_RING_COUNT];
> > + TEST_ASSERT(cur->pad == 0, "Padding is non-zero: 0x%x", cur->pad);
> > + TEST_ASSERT(cur->slot == slot, "Slot number didn't match: "
> > + "%u != %u", cur->slot, slot);
> > + TEST_ASSERT(cur->offset < num_pages, "Offset overflow: "
> > + "0x%llx >= 0x%llx", cur->offset, num_pages);
> > + DEBUG("fetch 0x%x offset 0x%llx\n", fetch, cur->offset);
> > + test_and_set_bit(cur->offset, bitmap);
> > + fetch++;
>
>
> Any reason to use test_and_set_bit()? I guess set_bit() should be
> sufficient.
Yes.
>
>
> > + count++;
> > + }
> > + WRITE_ONCE(indices->fetch_index, fetch);
>
>
> Is WRITE_ONCE a must here?
No.
[...]
> > +void *vcpu_map_dirty_ring(struct kvm_vm *vm, uint32_t vcpuid)
> > +{
> > + struct vcpu *vcpu;
> > + uint32_t size = vm->dirty_ring_size;
> > +
> > + TEST_ASSERT(size > 0, "Should enable dirty ring first");
> > +
> > + vcpu = vcpu_find(vm, vcpuid);
> > +
> > + TEST_ASSERT(vcpu, "Cannot find vcpu %u", vcpuid);
> > +
> > + if (!vcpu->dirty_gfns) {
> > + vcpu->dirty_gfns_count = size / sizeof(struct kvm_dirty_gfn);
> > + vcpu->dirty_gfns = mmap(NULL, size, PROT_READ | PROT_WRITE,
> > + MAP_SHARED, vcpu->fd, vm->page_size *
> > + KVM_DIRTY_LOG_PAGE_OFFSET);
>
>
> It looks to me that we don't write to dirty_gfn.
>
> So PROT_READ should be sufficient.
Yes. Thanks,
--
Peter Xu
next prev parent reply other threads:[~2019-12-24 15:22 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-21 1:49 [PATCH RESEND v2 00/17] KVM: Dirty ring interface Peter Xu
2019-12-21 1:49 ` [PATCH RESEND v2 01/17] KVM: Remove kvm_read_guest_atomic() Peter Xu
2020-01-08 17:45 ` Paolo Bonzini
2019-12-21 1:49 ` [PATCH RESEND v2 02/17] KVM: X86: Change parameter for fast_page_fault tracepoint Peter Xu
2020-01-08 17:46 ` Paolo Bonzini
2019-12-21 1:49 ` [PATCH RESEND v2 03/17] KVM: X86: Don't track dirty for KVM_SET_[TSS_ADDR|IDENTITY_MAP_ADDR] Peter Xu
2019-12-21 13:51 ` Paolo Bonzini
2019-12-23 17:27 ` Peter Xu
2019-12-23 17:59 ` Paolo Bonzini
2019-12-23 20:10 ` Peter Xu
2020-01-08 17:46 ` Paolo Bonzini
2020-01-08 19:15 ` Peter Xu
2020-01-08 19:44 ` Paolo Bonzini
2020-01-08 21:02 ` Peter Xu
2019-12-21 1:49 ` [PATCH RESEND v2 04/17] KVM: Cache as_id in kvm_memory_slot Peter Xu
2020-01-08 17:47 ` Paolo Bonzini
2019-12-21 1:49 ` [PATCH RESEND v2 05/17] KVM: Add build-time error check on kvm_run size Peter Xu
2019-12-21 1:49 ` [PATCH RESEND v2 06/17] KVM: Pass in kvm pointer into mark_page_dirty_in_slot() Peter Xu
2020-01-08 17:47 ` Paolo Bonzini
2019-12-21 1:49 ` [PATCH RESEND v2 07/17] KVM: Move running VCPU from ARM to common code Peter Xu
2020-01-08 17:47 ` Paolo Bonzini
2019-12-21 1:49 ` [PATCH RESEND v2 08/17] KVM: X86: Implement ring-based dirty memory tracking Peter Xu
2019-12-24 6:16 ` Jason Wang
2019-12-24 15:08 ` Peter Xu
2019-12-25 3:23 ` Jason Wang
2020-01-08 15:52 ` Peter Xu
2020-01-08 17:41 ` Paolo Bonzini
2020-01-08 19:06 ` Peter Xu
2020-01-08 19:44 ` Paolo Bonzini
2020-01-08 19:59 ` Peter Xu
2020-01-08 20:06 ` Paolo Bonzini
2019-12-21 1:49 ` [PATCH RESEND v2 09/17] KVM: Make dirty ring exclusive to dirty bitmap log Peter Xu
2019-12-21 1:58 ` [PATCH RESEND v2 10/17] KVM: Don't allocate dirty bitmap if dirty ring is enabled Peter Xu
2019-12-21 2:04 ` [PATCH RESEND v2 11/17] KVM: selftests: Always clear dirty bitmap after iteration Peter Xu
2019-12-21 2:04 ` [PATCH RESEND v2 12/17] KVM: selftests: Sync uapi/linux/kvm.h to tools/ Peter Xu
2019-12-21 2:04 ` [PATCH RESEND v2 13/17] KVM: selftests: Use a single binary for dirty/clear log test Peter Xu
2019-12-21 2:04 ` [PATCH RESEND v2 14/17] KVM: selftests: Introduce after_vcpu_run hook for dirty " Peter Xu
2019-12-21 2:04 ` [PATCH RESEND v2 15/17] KVM: selftests: Add dirty ring buffer test Peter Xu
2019-12-24 6:18 ` Jason Wang
2019-12-24 15:22 ` Peter Xu [this message]
2019-12-24 6:50 ` Jason Wang
2019-12-24 15:24 ` Peter Xu
2019-12-21 2:04 ` [PATCH RESEND v2 16/17] KVM: selftests: Let dirty_log_test async for dirty ring test Peter Xu
2019-12-21 2:04 ` [PATCH RESEND v2 17/17] KVM: selftests: Add "-c" parameter to dirty log test Peter Xu
2019-12-24 6:34 ` [PATCH RESEND v2 00/17] KVM: Dirty ring interface Jason Wang
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