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From: Paolo Bonzini <pbonzini@redhat.com>
To: Yang Weijiang <weijiang.yang@intel.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	sean.j.christopherson@intel.com, mst@redhat.com,
	rkrcmar@redhat.com, jmattson@google.com, yu.c.zhang@intel.com,
	alazar@bitdefender.com
Subject: Re: [PATCH RESEND v4 7/9] KVM: VMX: Handle SPP induced vmexit and page fault
Date: Thu, 22 Aug 2019 18:38:41 +0200
Message-ID: <62748fe8-0a3b-0554-452e-3bb5ebaf0466@redhat.com> (raw)
In-Reply-To: <20190822131745.GA20168@local-michael-cet-test>

On 22/08/19 15:17, Yang Weijiang wrote:
> On Tue, Aug 20, 2019 at 09:44:35PM +0800, Yang Weijiang wrote:
>> On Mon, Aug 19, 2019 at 05:04:23PM +0200, Paolo Bonzini wrote:
>>> fast_page_fault should never trigger an SPP userspace exit on its own,
>>> all the SPP handling should go through handle_spp.
>  Hi, Paolo,
>  According to the latest SDM(28.2.4), handle_spp only handles SPPT miss and SPPT
>  misconfig(exit_reason==66), subpage write access violation causes EPT violation,
>  so have to deal with the two cases into handlers.

Ok, so this part has to remain, though you do have to save/restore
PT_SPP_MASK according to the rest of the email.

Paolo

>>> So I think that when KVM wants to write-protect the whole page
>>> (wrprot_ad_disabled_spte) it must also clear PT_SPP_MASK; for example it
>>> could save it in bit 53 (PT64_SECOND_AVAIL_BITS_SHIFT + 1).  If the
>>> saved bit is set, fast_page_fault must then set PT_SPP_MASK instead of
>>> PT_WRITABLE_MASK.

  reply index

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-14  7:03 [PATCH RESEND v4 0/9] Enable Sub-page Write Protection Support Yang Weijiang
2019-08-14  7:03 ` [PATCH RESEND v4 1/9] Documentation: Introduce EPT based Subpage Protection Yang Weijiang
2019-08-14  7:03 ` [PATCH RESEND v4 2/9] KVM: VMX: Add control flags for SPP enabling Yang Weijiang
2019-08-14  7:03 ` [PATCH RESEND v4 3/9] KVM: VMX: Implement functions for SPPT paging setup Yang Weijiang
2019-08-14  7:03 ` [PATCH RESEND v4 4/9] KVM: VMX: Introduce SPP access bitmap and operation functions Yang Weijiang
2019-08-14  7:03 ` [PATCH RESEND v4 5/9] KVM: VMX: Add init/set/get functions for SPP Yang Weijiang
2019-08-14 12:43   ` Vitaly Kuznetsov
2019-08-14 14:34     ` Yang Weijiang
2019-08-15 13:43     ` Yang Weijiang
2019-08-15 14:03       ` Vitaly Kuznetsov
2019-08-19 14:06         ` Yang Weijiang
2019-08-15 16:25       ` Jim Mattson
2019-08-15 16:38         ` Sean Christopherson
2019-08-16 13:31           ` Yang Weijiang
2019-08-16 18:19             ` Jim Mattson
2019-08-19  2:08               ` Yang Weijiang
2019-08-19 15:15                 ` Paolo Bonzini
2019-08-20 12:33                   ` Yang Weijiang
2019-08-19 15:05   ` Paolo Bonzini
2019-08-20 12:36     ` Yang Weijiang
2019-08-19 15:13   ` Paolo Bonzini
2019-08-20 13:09     ` Yang Weijiang
2019-08-14  7:04 ` [PATCH RESEND v4 6/9] KVM: VMX: Introduce SPP user-space IOCTLs Yang Weijiang
2019-08-14  7:04 ` [PATCH RESEND v4 7/9] KVM: VMX: Handle SPP induced vmexit and page fault Yang Weijiang
2019-08-19 14:43   ` Paolo Bonzini
2019-08-19 15:04     ` Paolo Bonzini
2019-08-20 13:44       ` Yang Weijiang
2019-08-22 13:17         ` Yang Weijiang
2019-08-22 16:38           ` Paolo Bonzini [this message]
2019-08-23  0:26             ` Yang Weijiang
2019-08-14  7:04 ` [PATCH RESEND v4 8/9] KVM: MMU: Enable Lazy mode SPPT setup Yang Weijiang
2019-08-19 14:46   ` Paolo Bonzini
2019-08-20 13:12     ` Yang Weijiang
2019-09-04 13:49       ` Yang Weijiang
2019-09-09 17:10         ` Paolo Bonzini
2019-09-11  0:23           ` Yang Weijiang
2019-08-14  7:04 ` [PATCH RESEND v4 9/9] KVM: MMU: Handle host memory remapping and reclaim Yang Weijiang
2019-08-14 12:36 ` [PATCH RESEND v4 0/9] Enable Sub-page Write Protection Support Paolo Bonzini
2019-08-14 14:02   ` Yang Weijiang
2019-08-14 14:06     ` Paolo Bonzini

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