public inbox for kvm@vger.kernel.org
 help / color / mirror / Atom feed
From: Peter Xu <peterx@redhat.com>
To: Oliver Upton <oliver.upton@linux.dev>
Cc: Gavin Shan <gshan@redhat.com>,
	kvmarm@lists.linux.dev, kvmarm@lists.cs.columbia.edu,
	kvm@vger.kernel.org, catalin.marinas@arm.com, bgardon@google.com,
	shuah@kernel.org, andrew.jones@linux.dev, will@kernel.org,
	dmatlack@google.com, pbonzini@redhat.com, zhenyzha@redhat.com,
	james.morse@arm.com, suzuki.poulose@arm.com,
	alexandru.elisei@arm.com, seanjc@google.com,
	shan.gavin@gmail.com
Subject: Re: [PATCH v5 3/7] KVM: x86: Allow to use bitmap in ring-based dirty page tracking
Date: Tue, 18 Oct 2022 11:50:59 -0400	[thread overview]
Message-ID: <Y07LY41y6ZRL3d3S@x1n> (raw)
In-Reply-To: <Y05X4o1TxxkvES9E@google.com>

On Tue, Oct 18, 2022 at 10:38:10AM +0300, Oliver Upton wrote:
> If we ever get to the point that we can relax this restriction i think a
> flag on the BITMAP_WITH_TABLE cap that says "I don't actually set any
> bits in the bitmap" would do. We shouldn't hide the cap entirely, as
> that would be ABI breakage for VMMs that expect bitmap+ring.

I'd rather drop the cap directly if it's just a boolean that tells us
"whether we need bitmap to back rings". Btw when I said "dropping it" I
meant "don't return 1 for the cap anymore" - we definitely need to make the
cap macro stable as part of kvm API..

But I think I misunderstood the proposal previously, sorry. I assumed we
were discussing an internal HAVE_DIRTY_RING_WITH_BITMAP only.  I noticed
this only after I had a closer look at Gavin's patch.  Having a cap exposed
sounds always good to me.

I'll comment on Gavin's patch directly, thanks.

-- 
Peter Xu


  parent reply	other threads:[~2022-10-18 15:52 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-05  0:41 [PATCH v5 0/7] KVM: arm64: Enable ring-based dirty memory tracking Gavin Shan
2022-10-05  0:41 ` [PATCH v5 1/7] KVM: x86: Introduce KVM_REQ_RING_SOFT_FULL Gavin Shan
2022-10-05  0:41 ` [PATCH v5 2/7] KVM: x86: Move declaration of kvm_cpu_dirty_log_size() to kvm_dirty_ring.h Gavin Shan
2022-10-05  0:41 ` [PATCH v5 3/7] KVM: x86: Allow to use bitmap in ring-based dirty page tracking Gavin Shan
2022-10-06 20:28   ` Peter Xu
2022-10-06 23:38     ` Gavin Shan
2022-10-07 14:31       ` Peter Xu
2022-10-10 23:18         ` Oliver Upton
2022-10-10 23:43           ` Oliver Upton
2022-10-10 23:49           ` Peter Xu
2022-10-10 23:58             ` Gavin Shan
2022-10-10 23:58             ` Oliver Upton
2022-10-11  0:20               ` Peter Xu
2022-10-11  1:12                 ` Oliver Upton
2022-10-11  3:56                   ` Gavin Shan
2022-10-11  6:31                     ` Gavin Shan
2022-10-14 16:55                   ` Peter Xu
2022-10-18  7:38                     ` Oliver Upton
2022-10-18  7:40                       ` Oliver Upton
2022-10-18 15:50                       ` Peter Xu [this message]
2022-10-05  0:41 ` [PATCH v5 4/7] KVM: arm64: Enable ring-based dirty memory tracking Gavin Shan
2022-10-05  0:41 ` [PATCH v5 5/7] KVM: selftests: Use host page size to map ring buffer in dirty_log_test Gavin Shan
2022-10-05  0:41 ` [PATCH v5 6/7] KVM: selftests: Clear dirty ring states between two modes " Gavin Shan
2022-10-05  0:41 ` [PATCH v5 7/7] KVM: selftests: Automate choosing dirty ring size " Gavin Shan

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=Y07LY41y6ZRL3d3S@x1n \
    --to=peterx@redhat.com \
    --cc=alexandru.elisei@arm.com \
    --cc=andrew.jones@linux.dev \
    --cc=bgardon@google.com \
    --cc=catalin.marinas@arm.com \
    --cc=dmatlack@google.com \
    --cc=gshan@redhat.com \
    --cc=james.morse@arm.com \
    --cc=kvm@vger.kernel.org \
    --cc=kvmarm@lists.cs.columbia.edu \
    --cc=kvmarm@lists.linux.dev \
    --cc=oliver.upton@linux.dev \
    --cc=pbonzini@redhat.com \
    --cc=seanjc@google.com \
    --cc=shan.gavin@gmail.com \
    --cc=shuah@kernel.org \
    --cc=suzuki.poulose@arm.com \
    --cc=will@kernel.org \
    --cc=zhenyzha@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox