On Fri, Feb 09, 2018 at 11:38:50AM +0000, Julien Grall wrote:

Hi,

On 01/12/2018 12:07 PM, Christoffer Dall wrote:

quoted

From: Shih-Wei Li <redacted>

We always set the IMO and FMO bits in the HCR_EL2 when running the
guest, regardless if we use the vgic or not.  By moving these flags to
HCR_GUEST_FLAGS we can avoid one of the extra save/restore operations of
HCR_EL2 in the world switch code, and we can also soon get rid of the
other one.

This is safe, because even though the IMO and FMO bits control both
taking the interrupts to EL2 and remapping ICC_*_EL1 to ICV_*_EL1
executed at EL1, as long as we ensure that these bits are clear when
running the EL1 host, as defined in the HCR_HOST_[VHE_]FLAGS, we're OK.

NIT: I was a bit confused by the end of the sentence because HCR_HOST_FLAGS
define does not seem to exist.

True, that was nonsense.

I have reworded it slightly.

Thanks,
-Christoffer