Re: [Xen-devel] [PATCH v8 08/11] x86/pt: mask MSI vectors on unbind

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 23.01.18 at 16:07, <roger.pau@xxxxxxxxxx> wrote:
> When a MSI device with per-vector masking capabilities is detected or
> added to Xen all the vectors are masked when initializing it. This
> implies that the first time the interrupt is bound to a domain it's
> masked.
> 
> This however only applies to the first time the interrupt is bound
> because neither the unbind nor the pirq unmap will mask the vector
> again. In order to fix this re-mask the interrupt when unbinding it
> from a guest. This makes sure that pairs of bind/unbind will always
> get the same masking state.
> 
> Note that no issues have been reported regarding this behavior because
> QEMU always uses the newly introduced XEN_PT_GFLAGSSHIFT_UNMASKED when
> binding interrupts, so it's always unmasked.
> 
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>


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