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From: Yang Weijiang <weijiang.yang@intel.com>
To: Jim Mattson <jmattson@google.com>
Cc: "Yang Weijiang" <weijiang.yang@intel.com>,
	"kvm list" <kvm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Sean Christopherson" <sean.j.christopherson@intel.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	yu.c.zhang@intel.com, alazar@bitdefender.com
Subject: Re: [PATCH v5 0/9] Enable Sub-page Write Protection Support
Date: Fri, 11 Oct 2019 15:50:33 +0800	[thread overview]
Message-ID: <20191011075033.GA11817@local-michael-cet-test> (raw)
In-Reply-To: <CALMp9eSTz+XbmLtWZLqWvSNjjb4Ado4s+SfABtRuVNQBXUHStQ@mail.gmail.com>

On Thu, Oct 10, 2019 at 02:42:51PM -0700, Jim Mattson wrote:
> On Tue, Sep 17, 2019 at 1:52 AM Yang Weijiang <weijiang.yang@intel.com> wrote:
> >
> > EPT-Based Sub-Page write Protection(SPP)is a HW capability which allows
> > Virtual Machine Monitor(VMM) to specify write-permission for guest
> > physical memory at a sub-page(128 byte) granularity. When this
> > capability is enabled, the CPU enforces write-access check for sub-pages
> > within a 4KB page.
> >
> > The feature is targeted to provide fine-grained memory protection for
> > usages such as device virtualization, memory check-point and VM
> > introspection etc.
> >
> > SPP is active when the "sub-page write protection" (bit 23) is 1 in
> > Secondary VM-Execution Controls. The feature is backed with a Sub-Page
> > Permission Table(SPPT), SPPT is referenced via a 64-bit control field
> > called Sub-Page Permission Table Pointer (SPPTP) which contains a
> > 4K-aligned physical address.
> >
> > To enable SPP for certain physical page, the gfn should be first mapped
> > to a 4KB entry, then set bit 61 of the corresponding EPT leaf entry.
> > While HW walks EPT, if bit 61 is set, it traverses SPPT with the guset
> > physical address to find out the sub-page permissions at the leaf entry.
> > If the corresponding bit is set, write to sub-page is permitted,
> > otherwise, SPP induced EPT violation is generated.
> 
> How do you handle sub-page permissions for instructions emulated by kvm?
How about checking if the gpa is SPP protected, if it is, inject some
exception to guest? 

  reply	other threads:[~2019-10-11  7:48 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-17  8:52 [PATCH v5 0/9] Enable Sub-page Write Protection Support Yang Weijiang
2019-09-17  8:52 ` [PATCH v5 1/9] Documentation: Introduce EPT based Subpage Protection Yang Weijiang
2019-10-11 20:31   ` Jim Mattson
2019-10-15  8:53     ` Yang Weijiang
2019-09-17  8:52 ` [PATCH v5 2/9] vmx: spp: Add control flags for Sub-Page Protection(SPP) Yang Weijiang
2019-10-04 20:48   ` Jim Mattson
2019-10-04 21:02     ` Sean Christopherson
2019-10-15  1:53       ` Yang Weijiang
2019-09-17  8:52 ` [PATCH v5 3/9] mmu: spp: Add SPP Table setup functions Yang Weijiang
2019-09-17  8:52 ` [PATCH v5 4/9] mmu: spp: Add functions to create/destroy SPP bitmap block Yang Weijiang
2019-09-17  8:53 ` [PATCH v5 5/9] mmu: spp: Introduce SPP {init,set,get} functions Yang Weijiang
2019-09-17  8:53 ` [PATCH v5 6/9] x86: spp: Introduce user-space SPP IOCTLs Yang Weijiang
2019-09-17  8:53 ` [PATCH v5 7/9] vmx: spp: Set up SPP paging table at vm-entry/exit Yang Weijiang
2019-09-17 10:56   ` kbuild test robot
2019-09-17  8:53 ` [PATCH v5 8/9] mmu: spp: Enable Lazy mode SPP protection Yang Weijiang
2019-09-17  8:53 ` [PATCH v5 9/9] mmu: spp: Handle SPP protected pages when VM memory changes Yang Weijiang
2019-09-17 12:59 ` [PATCH v5 0/9] Enable Sub-page Write Protection Support Konrad Rzeszutek Wilk
2019-09-17 16:24   ` Adalbert Lazăr
2019-10-09  2:17 ` Yang Weijiang
2019-10-10 21:42 ` Jim Mattson
2019-10-11  7:50   ` Yang Weijiang [this message]
2019-10-11 16:11     ` Jim Mattson
2019-10-22  6:19       ` Yang Weijiang

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