Re: [PATCH v2 1/3] xen/pv: allow pmu msr accesses to cause GP

From: Jan Beulich
Date: Tue Oct 04 2022 - 11:50:57 EST

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@xxxxxxxx>
>> 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.