From: Peter Xu <peterx@redhat.com>
To: Paolo Bonzini <pbonzini@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>,
"Michael S . Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>
Subject: Re: [PATCH RESEND v2 03/17] KVM: X86: Don't track dirty for KVM_SET_[TSS_ADDR|IDENTITY_MAP_ADDR]
Date: Mon, 23 Dec 2019 12:27:37 -0500 [thread overview]
Message-ID: <20191223172737.GA81196@xz-x1> (raw)
In-Reply-To: <cf232ce8-bc07-0192-580f-d08736980273@redhat.com>
On Sat, Dec 21, 2019 at 02:51:52PM +0100, Paolo Bonzini wrote:
> On 21/12/19 02:49, Peter Xu wrote:
> > Originally, we have three code paths that can dirty a page without
> > vcpu context for X86:
> >
> > - init_rmode_identity_map
> > - init_rmode_tss
> > - kvmgt_rw_gpa
> >
> > init_rmode_identity_map and init_rmode_tss will be setup on
> > destination VM no matter what (and the guest cannot even see them), so
> > it does not make sense to track them at all.
> >
> > To do this, a new parameter is added to kvm_[write|clear]_guest_page()
> > to show whether we would like to track dirty bits for the operations.
> > With that, pass in "false" to this new parameter for any guest memory
> > write of the ioctls (KVM_SET_TSS_ADDR, KVM_SET_IDENTITY_MAP_ADDR).
>
> We can also return the hva from x86_set_memory_region and
> __x86_set_memory_region.
Yes. Though it is a bit tricky in that then we'll also need to make
sure to take slots_lock or srcu to protect that hva (say, we must drop
that hva reference before we release the locks, otherwise the hva
could gone under us, iiuc). So if we want to do that we'd better
comment on that hva value very explicitly, just in case some future
callers of __x86_set_memory_region could cache it somewhere.
(Side topic: I feel like the srcu_read_lock() pair in
init_rmode_identity_map() is redundant..)
--
Peter Xu
next prev parent reply other threads:[~2019-12-23 17:27 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 [this message]
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
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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