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From: "Liu, Jing2" <jing2.liu@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	"Tian, Kevin" <kevin.tian@intel.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>,
	"jing2.liu@linux.intel.com" <jing2.liu@linux.intel.com>
Subject: RE: [PATCH 09/19] kvm: x86: Prepare reallocation check
Date: Tue, 14 Dec 2021 14:41:46 +0000	[thread overview]
Message-ID: <MWHPR11MB12453B3CE026CE7087C29E3FA9759@MWHPR11MB1245.namprd11.prod.outlook.com> (raw)
In-Reply-To: <d513db49-bb94-becf-be7e-f26dceb3e1bf@redhat.com>


On 12/14/2021 6:16 PM, Paolo Bonzini wrote:
> 
> On 12/14/21 08:06, Tian, Kevin wrote:
> >> - if (dynamic_enabled & ~guest_fpu->user_perm) != 0, then this is a
> >> userspace error and you can #GP the guest without any issue.
> >> Userspace is buggy
> >
> > Is it a general guideline that an error caused by emulation itself (e.g.
> > due to no memory) can be reflected into the guest as #GP, even when
> > from guest p.o.v there is nothing wrong with its setting?
> 
> No memory is a tricky one, if possible it should propagate -ENOMEM up to
> KVM_RUN or KVM_SET_MSR.  But it's basically an impossible case anyway,
> because even with 8K TILEDATA we're within the limit of
> PAGE_ALLOC_COSTLY_ORDER.
> 
> So, since it's not easy to do it right now, we can look at it later.

For the way handling xcr0 and xfd ioctl failure, xcr0 and xfd have 
different handlings. Current KVM_SET_XCRS returns -EINVAL to 
userspace. KVM_SET_MSR is always allowed as the discussion in 
another thread.

So I'm thinking if reallocation failure in KVM_SET_XCRS and 
KVM_SET_MSR (may due to NOMEM or EPERM or ENOTSUPP), 
what is the way we would like to choose?

Thanks,
Jing
 
> Paolo

  reply	other threads:[~2021-12-14 14:41 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 [this message]
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
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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