From: Sean Christopherson <seanjc@google.com>
To: Yan Zhao <yan.y.zhao@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Zhenyu Wang <zhenyuw@linux.intel.com>,
Zhi Wang <zhi.a.wang@intel.com>,
kvm@vger.kernel.org, intel-gvt-dev@lists.freedesktop.org,
intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org,
Ben Gardon <bgardon@google.com>
Subject: Re: [PATCH 26/27] KVM: x86/mmu: Add page-track API to query if a gfn is valid
Date: Thu, 5 Jan 2023 17:53:59 +0000 [thread overview]
Message-ID: <Y7cOt5R/wK2Y1fg5@google.com> (raw)
In-Reply-To: <Y7ZAEsQbNbWKngGi@yzhao56-desk.sh.intel.com>
On Thu, Jan 05, 2023, Yan Zhao wrote:
> On Tue, Jan 03, 2023 at 09:19:01PM +0000, Sean Christopherson wrote:
> > On Wed, Dec 28, 2022, Yan Zhao wrote:
> > > On Fri, Dec 23, 2022 at 12:57:38AM +0000, Sean Christopherson wrote:
> > > > +bool kvm_page_track_is_valid_gfn(struct kvm *kvm, gfn_t gfn)
> > > > +{
> > > > + bool ret;
> > > > + int idx;
> > > > +
> > > > + idx = srcu_read_lock(&kvm->srcu);
> > > > + ret = kvm_is_visible_gfn(kvm, gfn);
> > > > + srcu_read_unlock(&kvm->srcu, idx);
> > > > +
> > > > + return ret;
> > > > +}
> > > > +EXPORT_SYMBOL_GPL(kvm_page_track_is_valid_gfn);
> > > This implementation is only to check whether a GFN is within a visible
> > > kvm memslot. So, why this helper function is named kvm_page_track_xxx()?
> > > Don't think it's anything related to page track, and not all of its callers
> > > in KVMGT are for page tracking.
> >
> > KVMGT is the only user of kvm_page_track_is_valid_gfn(). kvm_is_visible_gfn()
> > has other users, just not in x86. And long term, my goal is to allow building
> > KVM x86 without any exports. Killing off KVM's "internal" (for vendor modules)
> > exports for select Kconfigs is easy enough, add adding a dedicated page-track API
> > solves the KVMGT angle.
> Understand!
> But personally, I don't like merging this API into page-track API as
> it obviously has nothing to do with page-track stuffs, and KVMGT also calls it for
> non-page-track purpuse.
100% agreed, but as discussed in the other patch[*], IMO the real issue is that
KVMGT is abusing KVM APIs to check the validity of GFNs that are ultimately mapped
via VFIO. Once that issue is fixed, kvm_page_track_is_valid_gfn() can go away
entirely. I view this as a short/medium term hack-a-fix to limit and encapsulate
KVM's API surface that is "needed" by KVMGT.
[*] https://lore.kernel.org/all/Y7cLkLUMCy+XLRwm@google.com
next prev parent reply other threads:[~2023-01-05 17:54 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-23 0:57 [PATCH 00/27] drm/i915/gvt: KVM: KVMGT fixes and page-track cleanups Sean Christopherson
2022-12-23 0:57 ` [PATCH 01/27] drm/i915/gvt: Verify pfn is "valid" before dereferencing "struct page" Sean Christopherson
2022-12-23 0:57 ` [PATCH 02/27] KVM: x86/mmu: Factor out helper to get max mapping size of a memslot Sean Christopherson
2022-12-23 0:57 ` [PATCH 03/27] drm/i915/gvt: Incorporate KVM memslot info into check for 2MiB GTT entry Sean Christopherson
2022-12-28 5:42 ` Yan Zhao
2023-01-03 21:13 ` Sean Christopherson
2023-01-05 3:07 ` Yan Zhao
2023-01-05 17:40 ` Sean Christopherson
2023-01-06 5:56 ` Yan Zhao
2023-01-06 23:01 ` Sean Christopherson
2023-01-09 9:58 ` Yan Zhao
2023-01-11 17:55 ` Sean Christopherson
2023-01-19 2:58 ` Zhenyu Wang
2023-01-19 5:26 ` Yan Zhao
2023-02-23 20:41 ` Sean Christopherson
2023-02-24 5:09 ` Yan Zhao
2023-01-12 8:31 ` Yan Zhao
2022-12-23 0:57 ` [PATCH 04/27] drm/i915/gvt: Verify VFIO-pinned page is THP when shadowing 2M gtt entry Sean Christopherson
2022-12-23 0:57 ` [PATCH 05/27] drm/i915/gvt: Put the page reference obtained by KVM's gfn_to_pfn() Sean Christopherson
2022-12-23 0:57 ` [PATCH 06/27] drm/i915/gvt: Don't rely on KVM's gfn_to_pfn() to query possible 2M GTT Sean Christopherson
2022-12-23 0:57 ` [PATCH 07/27] drm/i915/gvt: Use an "unsigned long" to iterate over memslot gfns Sean Christopherson
2022-12-23 0:57 ` [PATCH 08/27] drm/i915/gvt: Hoist acquisition of vgpu_lock out to kvmgt_page_track_write() Sean Christopherson
2022-12-23 0:57 ` [PATCH 09/27] drm/i915/gvt: Protect gfn hash table with dedicated mutex Sean Christopherson
2022-12-28 5:03 ` Yan Zhao
2023-01-03 20:43 ` Sean Christopherson
2023-01-05 0:51 ` Yan Zhao
2022-12-23 0:57 ` [PATCH 10/27] KVM: x86/mmu: Don't rely on page-track mechanism to flush on memslot change Sean Christopherson
2022-12-23 0:57 ` [PATCH 11/27] KVM: x86/mmu: Don't bounce through page-track mechanism for guest PTEs Sean Christopherson
2022-12-23 0:57 ` [PATCH 12/27] KVM: drm/i915/gvt: Drop @vcpu from KVM's ->track_write() hook Sean Christopherson
2022-12-23 0:57 ` [PATCH 13/27] KVM: x86: Reject memslot MOVE operations if KVMGT is attached Sean Christopherson
2022-12-23 0:57 ` [PATCH 14/27] drm/i915/gvt: Don't bother removing write-protection on to-be-deleted slot Sean Christopherson
2022-12-23 0:57 ` [PATCH 15/27] KVM: x86: Add a new page-track hook to handle memslot deletion Sean Christopherson
2022-12-23 0:57 ` [PATCH 16/27] drm/i915/gvt: switch from ->track_flush_slot() to ->track_remove_region() Sean Christopherson
2022-12-23 0:57 ` [PATCH 17/27] KVM: x86: Remove the unused page-track hook track_flush_slot() Sean Christopherson
2022-12-23 0:57 ` [PATCH 18/27] KVM: x86/mmu: Move KVM-only page-track declarations to internal header Sean Christopherson
2022-12-23 0:57 ` [PATCH 19/27] KVM: x86/mmu: Use page-track notifiers iff there are external users Sean Christopherson
2022-12-28 6:56 ` Yan Zhao
2023-01-04 0:50 ` Sean Christopherson
2023-08-07 12:01 ` Like Xu
2023-08-07 17:19 ` Sean Christopherson
2023-08-09 1:02 ` Yan Zhao
2023-08-09 14:33 ` Sean Christopherson
2023-08-09 23:21 ` Yan Zhao
2023-08-10 3:02 ` Yan Zhao
2023-08-10 15:41 ` Sean Christopherson
2023-08-11 5:57 ` Yan Zhao
2022-12-23 0:57 ` [PATCH 20/27] KVM: x86/mmu: Drop infrastructure for multiple page-track modes Sean Christopherson
2022-12-23 0:57 ` [PATCH 21/27] KVM: x86/mmu: Rename page-track APIs to reflect the new reality Sean Christopherson
2022-12-23 0:57 ` [PATCH 22/27] KVM: x86/mmu: Assert that correct locks are held for page write-tracking Sean Christopherson
2022-12-23 0:57 ` [PATCH 23/27] KVM: x86/mmu: Bug the VM if write-tracking is used but not enabled Sean Christopherson
2022-12-23 0:57 ` [PATCH 24/27] KVM: x86/mmu: Drop @slot param from exported/external page-track APIs Sean Christopherson
2022-12-23 0:57 ` [PATCH 25/27] KVM: x86/mmu: Handle KVM bookkeeping in page-track APIs, not callers Sean Christopherson
2022-12-23 0:57 ` [PATCH 26/27] KVM: x86/mmu: Add page-track API to query if a gfn is valid Sean Christopherson
2022-12-28 7:57 ` Yan Zhao
2023-01-03 21:19 ` Sean Christopherson
2023-01-05 3:12 ` Yan Zhao
2023-01-05 17:53 ` Sean Christopherson [this message]
2022-12-23 0:57 ` [PATCH 27/27] drm/i915/gvt: Drop final dependencies on KVM internal details Sean Christopherson
2022-12-23 9:05 ` [PATCH 00/27] drm/i915/gvt: KVM: KVMGT fixes and page-track cleanups Yan Zhao
2023-01-04 1:01 ` Sean Christopherson
2023-01-05 3:13 ` Yan Zhao
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=Y7cOt5R/wK2Y1fg5@google.com \
--to=seanjc@google.com \
--cc=bgardon@google.com \
--cc=intel-gfx@lists.freedesktop.org \
--cc=intel-gvt-dev@lists.freedesktop.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=yan.y.zhao@intel.com \
--cc=zhenyuw@linux.intel.com \
--cc=zhi.a.wang@intel.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