Hi Wei,
On 31/03/17 14:07, Wei Chen wrote:
Different domains may have different HCR_EL2 flags. For example, the
64-bit domain needs HCR_RW flag but the 32-bit does not need it. So
we give each domain a default HCR_EL2 value and save it in the vCPU's
context.
HCR_EL2 register has only one bit can be updated automatically without
explicit write (HCR_VSE). But we haven't used this bit currently, so
we can consider that the HCR_EL2 register will not be modified while
the guest is running. So save the HCR_EL2 while guest exiting to
hypervisor is not neccessary. We just have to restore this register for
each vCPU while context switching.
The p2m_restore_state which will be invoked in context switch progress
has included the writing of HCR_EL2 already. It updates the HCR_EL2.RW
bit to tell the hardware how to interpret the stage-1 page table as the
encodings are different between AArch64 and AArch32. We can reuse this
write to restore the HCR_EL2 for each vCPU. Of course, the value of each
vCPU's HCR_EL2 should be adjusted to have proper HCR_EL2.RW bit in this
function. In the later patch of this series, we will set the HCR_EL2.RW
for each vCPU while the domain is creating.
Signed-off-by: wei chen <wei.c...@arm.com>
Reviewed-by: Julien Grall <julien.gr...@arm.com>
Cheers,
--
Julien Grall
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