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From: Jan Beulich <jbeulich@suse.com>
To: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
	x86@kernel.org
Subject: Re: [PATCH v2 1/3] xen/pv: allow pmu msr accesses to cause GP
Date: Tue, 4 Oct 2022 17:50:44 +0200	[thread overview]
Message-ID: <7a453c41-37ca-6fdf-90e6-333c35fe9489@suse.com> (raw)
In-Reply-To: <e5d0e772-ec9e-049a-da85-960c14520f8c@suse.com>

On 04.10.2022 17:22, Juergen Gross wrote:
> On 04.10.22 12:58, Jan Beulich wrote:
>> On 04.10.2022 10:43, Juergen Gross wrote:
>>> Today pmu_msr_read() and pmu_msr_write() fall back to the safe variants
>>> of read/write MSR in case the MSR access isn't emulated via Xen. Allow
>>> the caller to select the potentially faulting variant by passing NULL
>>> for the error pointer.
>>>
>>> Restructure the code to make it more readable.
>>>
>>> Signed-off-by: Juergen Gross <jgross@suse.com>
>>
>> I think the title (and to some degree also the description) is misleading:
>> The property we care about here isn't whether an MSR access would raise
>> #GP (we can't control that), but whether that #GP would be recovered from.
> 
> Would you be fine with adding "fatal" or "visible"?

That would help, but "allow" also is a little odd when it comes to
(likely) crashing the system.

Jan

  reply	other threads:[~2022-10-04 15:50 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-04  8:43 [PATCH v2 0/3] xen/pv: sanitize xen pv guest msr accesses Juergen Gross
2022-10-04  8:43 ` [PATCH v2 1/3] xen/pv: allow pmu msr accesses to cause GP Juergen Gross
2022-10-04 10:58   ` Jan Beulich
2022-10-04 15:22     ` Juergen Gross
2022-10-04 15:50       ` Jan Beulich [this message]
2022-10-04 19:46   ` Boris Ostrovsky
2022-10-04  8:43 ` [PATCH v2 2/3] xen/pv: refactor msr access functions to support safe and unsafe accesses Juergen Gross
2022-10-04 11:03   ` Jan Beulich
2022-10-04 15:33     ` Juergen Gross
2022-10-04  8:43 ` [PATCH v2 3/3] xen/pv: support selecting safe/unsafe msr accesses Juergen Gross

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