From: Xiao Guangrong <guangrong.xiao@linux.intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Huaitong Han <huaitong.han@intel.com>,
gleb@kernel.org
Cc: kvm@vger.kernel.org
Subject: Re: [PATCH V4 7/7] KVM, pkeys: disable PKU feature without ept
Date: Tue, 8 Mar 2016 13:54:33 +0800 [thread overview]
Message-ID: <56DE6919.4060107@linux.intel.com> (raw)
In-Reply-To: <56DC93D1.2070204@redhat.com>
On 03/07/2016 04:32 AM, Paolo Bonzini wrote:
>
>
> On 06/03/2016 10:28, Xiao Guangrong wrote:
>>> This patch disables CPUID:PKU without ept, because pkeys is not yet
>>> implemented for shadow paging.
>>
>> Does the PKRU is loaded/saved during vm-enter/vm-exit?
>
> Yes, through XSAVE/XRSTOR (which uses eager mode when PKE is active).
You mean eager fpu? however, eager-fpu depends on 'eagerfpu' which is a kernel
parameter and this patchset did not force it on.
However, even if we use eager-fpu kvm still can lazily save/load due to some
fpu optimizations in kvm.
>> BTW, I just very quickly go through the spec, it seems VMX lacks the
>> ability to intercept the access to PKRU. Right?
>
> Indeed RDPKRU/WRPKRU cannot be intercepted.
Er, i was thinking using this feature to speedup write-protection for
shadow page table and dirty-logging... it seems not easy as PKRU can not
be intercepted. :(
next prev parent reply other threads:[~2016-03-08 5:54 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-05 11:27 [PATCH V4 0/7] KVM, pkeys: add memory protection-key support Huaitong Han
2016-03-05 11:27 ` [PATCH V4 1/7] KVM, pkeys: expose CPUID/CR4 to guest Huaitong Han
2016-03-06 7:15 ` Xiao Guangrong
2016-03-06 23:20 ` Paolo Bonzini
2016-03-08 7:39 ` Xiao Guangrong
2016-03-08 7:58 ` Paolo Bonzini
2016-03-05 11:27 ` [PATCH V4 2/7] KVM, pkeys: disable pkeys for guests in non-paging mode Huaitong Han
2016-03-06 7:19 ` Xiao Guangrong
2016-03-08 12:09 ` Yang Zhang
2016-03-08 12:11 ` Paolo Bonzini
2016-03-08 13:02 ` Yang Zhang
2016-03-05 11:27 ` [PATCH V4 3/7] KVM, pkeys: update memeory permission bitmask for pkeys Huaitong Han
2016-03-06 7:42 ` Xiao Guangrong
2016-03-06 23:14 ` Paolo Bonzini
2016-03-08 7:35 ` Xiao Guangrong
2016-03-08 8:29 ` Paolo Bonzini
2016-03-08 9:19 ` Xiao Guangrong
2016-03-08 10:01 ` Paolo Bonzini
2016-03-09 5:03 ` Xiao Guangrong
2016-03-09 8:10 ` Paolo Bonzini
2016-03-05 11:27 ` [PATCH V4 4/7] KVM, pkeys: add pkeys support for permission_fault logic Huaitong Han
2016-03-06 8:00 ` Xiao Guangrong
2016-03-06 20:36 ` Paolo Bonzini
2016-03-06 23:29 ` Paolo Bonzini
2016-03-08 5:57 ` Xiao Guangrong
2016-03-05 11:27 ` [PATCH V4 5/7] KVM, pkeys: Add pkeys support for gva_to_gpa funcions Huaitong Han
2016-03-06 8:01 ` Xiao Guangrong
2016-03-06 21:33 ` Paolo Bonzini
2016-03-05 11:27 ` [PATCH V4 6/7] KVM, pkeys: add pkeys support for xsave state Huaitong Han
2016-03-06 8:27 ` Xiao Guangrong
2016-03-05 11:27 ` [PATCH V4 7/7] KVM, pkeys: disable PKU feature without ept Huaitong Han
2016-03-06 9:28 ` Xiao Guangrong
2016-03-06 20:32 ` Paolo Bonzini
2016-03-08 5:54 ` Xiao Guangrong [this message]
2016-03-08 8:47 ` Paolo Bonzini
2016-03-08 9:32 ` Xiao Guangrong
2016-03-08 10:02 ` Paolo Bonzini
2016-03-09 5:51 ` Xiao Guangrong
2016-03-09 6:37 ` Yang Zhang
2016-03-09 7:21 ` Xiao Guangrong
2016-03-09 7:41 ` Yang Zhang
2016-03-09 7:50 ` Xiao Guangrong
2016-03-09 8:00 ` Yang Zhang
2016-03-09 8:05 ` Xiao Guangrong
2016-03-09 8:18 ` Paolo Bonzini
2016-03-09 8:13 ` Paolo Bonzini
2016-03-09 6:24 ` Yang Zhang
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