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From: "Liu, Jing2" <jing2.liu@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	"Zhong, Yang" <yang.zhong@intel.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"bp@alien8.de" <bp@alien8.de>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>
Cc: "Christopherson,, Sean" <seanjc@google.com>,
	"Nakajima, Jun" <jun.nakajima@intel.com>,
	"Tian, Kevin" <kevin.tian@intel.com>,
	"jing2.liu@linux.intel.com" <jing2.liu@linux.intel.com>,
	"Wang, Wei W" <wei.w.wang@intel.com>,
	"Zeng, Guang" <guang.zeng@intel.com>
Subject: RE: [PATCH 10/19] kvm: x86: Emulate WRMSR of guest IA32_XFD
Date: Mon, 13 Dec 2021 07:51:27 +0000	[thread overview]
Message-ID: <MWHPR11MB1245F7730D9BF0DA251D302DA9749@MWHPR11MB1245.namprd11.prod.outlook.com> (raw)
In-Reply-To: <fd16797c-b80f-c414-a731-0b9b73a3732e@redhat.com>

On 12/11/2021 12:02 AM, Paolo Bonzini wrote:
> 
> Also:
> 
> On 12/8/21 01:03, Yang Zhong wrote:
> >
> > +		if (!guest_cpuid_has(vcpu, X86_FEATURE_XFD))
> > +			return 1;
> 
> This should allow msr->host_initiated always (even if XFD is not part of
> CPUID). 
Thanks Paolo.

msr->host_initiated handling would be added in next version.

I'd like to ask why always allow msr->host_initiated even if XFD is not part of
CPUID, although guest doesn't care that MSR?  We found some MSRs
 (e.g. MSR_AMD64_OSVW_STATUS and MSR_AMD64_OSVW_ID_LENGTH ) 
are specially handled so would like to know the consideration of allowing
msr->host_initiated.

if (!msr_info->host_initiated && !guest_cpuid_has(vcpu, X86_FEATURE_XFD))
        return 1;


 However, if XFD is nonzero and kvm_check_guest_realloc_fpstate
> returns true, then it should return 1.
> 
If XFD is nonzero, kvm_check_guest_realloc_fpstate() won't return true. So
may not need this check here?

Thanks,
Jing

> 
> Paolo

  reply	other threads:[~2021-12-13  7:51 UTC|newest]

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-08  0:03 [PATCH 00/19] AMX Support in KVM Yang Zhong
2021-12-08  0:03 ` [PATCH 01/19] x86/fpu: Extend prctl() with guest permissions Yang Zhong
2021-12-14  0:16   ` Thomas Gleixner
2021-12-08  0:03 ` [PATCH 02/19] x86/fpu: Prepare KVM for dynamically enabled states Yang Zhong
2021-12-13  9:12   ` Paolo Bonzini
2021-12-13 12:00     ` Thomas Gleixner
2021-12-13 12:45       ` Paolo Bonzini
2021-12-13 19:50         ` Thomas Gleixner
2021-12-08  0:03 ` [PATCH 03/19] kvm: x86: Fix xstate_required_size() to follow XSTATE alignment rule Yang Zhong
2021-12-08  0:03 ` [PATCH 04/19] kvm: x86: Check guest xstate permissions when KVM_SET_CPUID2 Yang Zhong
2021-12-08  0:03 ` [PATCH 05/19] x86/fpu: Move xfd initialization out of __fpstate_reset() to the callers Yang Zhong
2021-12-10 22:33   ` Thomas Gleixner
2021-12-08  0:03 ` [PATCH 06/19] x86/fpu: Add reallocation mechanims for KVM Yang Zhong
2021-12-08  0:03 ` [PATCH 07/19] kvm: x86: Propagate fpstate reallocation error to userspace Yang Zhong
2021-12-10 15:44   ` Paolo Bonzini
2021-12-08  0:03 ` [PATCH 08/19] x86/fpu: Move xfd_update_state() to xstate.c and export symbol Yang Zhong
2021-12-10 22:44   ` Thomas Gleixner
2021-12-08  0:03 ` [PATCH 09/19] kvm: x86: Prepare reallocation check Yang Zhong
2021-12-13  9:16   ` Paolo Bonzini
2021-12-14  7:06     ` Tian, Kevin
2021-12-14 10:16       ` Paolo Bonzini
2021-12-14 14:41         ` Liu, Jing2
2021-12-15  7:09           ` Tian, Kevin
2021-12-08  0:03 ` [PATCH 10/19] kvm: x86: Emulate WRMSR of guest IA32_XFD Yang Zhong
2021-12-10 16:02   ` Paolo Bonzini
2021-12-13  7:51     ` Liu, Jing2 [this message]
2021-12-13  9:01       ` Paolo Bonzini
2021-12-14 10:26     ` Yang Zhong
2021-12-14 11:24       ` Paolo Bonzini
2021-12-10 23:09   ` Thomas Gleixner
2021-12-13 15:06   ` Paolo Bonzini
2021-12-13 19:45     ` Thomas Gleixner
2021-12-13 21:23       ` Thomas Gleixner
2021-12-14  7:16         ` Tian, Kevin
2021-12-08  0:03 ` [PATCH 11/19] kvm: x86: Check fpstate reallocation in XSETBV emulation Yang Zhong
2021-12-08  0:03 ` [PATCH 12/19] x86/fpu: Prepare KVM for bringing XFD state back in-sync Yang Zhong
2021-12-10 23:11   ` Thomas Gleixner
2021-12-08  0:03 ` [PATCH 13/19] kvm: x86: Disable WRMSR interception for IA32_XFD on demand Yang Zhong
2021-12-08  7:23   ` Liu, Jing2
2021-12-08  0:03 ` [PATCH 14/19] x86/fpu: Prepare for KVM XFD_ERR handling Yang Zhong
2021-12-10 16:16   ` Paolo Bonzini
2021-12-10 23:20   ` Thomas Gleixner
2021-12-08  0:03 ` [PATCH 15/19] kvm: x86: Save and restore guest XFD_ERR properly Yang Zhong
2021-12-10 16:23   ` Paolo Bonzini
2021-12-10 22:01   ` Paolo Bonzini
2021-12-12 13:10     ` Yang Zhong
2021-12-11  0:10   ` Thomas Gleixner
2021-12-11  1:31     ` Paolo Bonzini
2021-12-11  3:23       ` Tian, Kevin
2021-12-11 13:10       ` Thomas Gleixner
2021-12-11  3:07     ` Tian, Kevin
2021-12-11 13:29       ` Thomas Gleixner
2021-12-12  1:50         ` Tian, Kevin
2021-12-12  9:10           ` Paolo Bonzini
2021-12-08  0:03 ` [PATCH 16/19] kvm: x86: Introduce KVM_{G|S}ET_XSAVE2 ioctl Yang Zhong
2021-12-10 16:25   ` Paolo Bonzini
2021-12-10 16:30   ` Paolo Bonzini
2021-12-10 22:13     ` Paolo Bonzini
2021-12-13  8:23       ` Wang, Wei W
2021-12-13  9:24         ` Paolo Bonzini
2021-12-14  6:06           ` Wang, Wei W
2021-12-14  6:18             ` Paolo Bonzini
2021-12-15  2:39               ` Wang, Wei W
2021-12-15 13:42                 ` Paolo Bonzini
2021-12-16  8:25                   ` Wang, Wei W
2021-12-16 10:28                     ` Paolo Bonzini
2021-12-20 17:54       ` State Component 18 and Palette 1 (Re: [PATCH 16/19] kvm: x86: Introduce KVM_{G|S}ET_XSAVE2 ioctl) Nakajima, Jun
2021-12-22 14:44         ` Paolo Bonzini
2021-12-22 23:47           ` Nakajima, Jun
2021-12-22 14:52         ` Dave Hansen
2021-12-22 23:51           ` Nakajima, Jun
2021-12-13 10:10     ` [PATCH 16/19] kvm: x86: Introduce KVM_{G|S}ET_XSAVE2 ioctl Thomas Gleixner
2021-12-13 10:43       ` Paolo Bonzini
2021-12-13 12:40         ` Thomas Gleixner
2021-12-08  0:03 ` [PATCH 17/19] docs: virt: api.rst: Document the new KVM_{G, S}ET_XSAVE2 ioctls Yang Zhong
2021-12-08  0:03 ` [PATCH 18/19] kvm: x86: AMX XCR0 support for guest Yang Zhong
2021-12-10 16:30   ` Paolo Bonzini
2021-12-08  0:03 ` [PATCH 19/19] kvm: x86: Add AMX CPUIDs support Yang Zhong
2021-12-10 21:52   ` Paolo Bonzini
2021-12-11 21:20 ` [PATCH 00/19] AMX Support in KVM Thomas Gleixner

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