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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Jim Mattson <jmattson@google.com>
Cc: "Yang Weijiang" <weijiang.yang@intel.com>,
	"Vitaly Kuznetsov" <vkuznets@redhat.com>,
	"kvm list" <kvm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	yu.c.zhang@intel.com, alazar@bitdefender.com,
	"Paolo Bonzini" <pbonzini@redhat.com>
Subject: Re: [PATCH RESEND v4 5/9] KVM: VMX: Add init/set/get functions for SPP
Date: Thu, 15 Aug 2019 09:38:44 -0700
Message-ID: <20190815163844.GD27076@linux.intel.com> (raw)
In-Reply-To: <CALMp9eTGXDDfVspFwFyEhagg9sdnqZqzSQhDksT0bkKzVNGSqw@mail.gmail.com>

On Thu, Aug 15, 2019 at 09:25:41AM -0700, Jim Mattson wrote:
> On Thu, Aug 15, 2019 at 6:41 AM Yang Weijiang <weijiang.yang@intel.com> wrote:
> 
> > Hi, Vitaly,
> > After looked into the issue and others, I feel to make SPP co-existing
> > with nested VM is not good, the major reason is, L1 pages protected by
> > SPP are transparent to L1 VM, if it launches L2 VM, probably the
> > pages would be allocated to L2 VM, and that will bother to L1 and L2.
> > Given the feature is new and I don't see nested VM can benefit
> > from it right now, I would like to make SPP and nested feature mutually
> > exclusive, i.e., detecting if the other part is active before activate one
> > feature,what do you think of it?
> > thanks!
> 
> How do you propose making the features mutually exclusive?

I haven't looked at the details or the end to end flow, but would it make
sense to exit to userspace on nested VMLAUNCH/VMRESUME if there are SPP
mappings?  And have the SPP ioctl() kick vCPUs out of guest.

KVM already exits on SPP violations, so presumably this is something that
can be punted to userspace.

  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 [this message]
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
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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