On 2022-11-19 05:52, Reiji Watanabe wrote:
Hi Marc,
On Sun, Nov 13, 2022 at 8:46 AM Marc Zyngier <maz@xxxxxxxxxx> wrote:
Allow userspace to write ID_DFR0_EL1, on the condition that only
the PerfMon field can be altered and be something that is compatible
with what was computed for the AArch64 view of the guest.
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
arch/arm64/kvm/sys_regs.c | 57
++++++++++++++++++++++++++++++++++++++-
1 file changed, 56 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 3cbcda665d23..dc201a0557c0 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1070,6 +1070,19 @@ static u8 vcpu_pmuver(const struct kvm_vcpu
*vcpu)
return vcpu->kvm->arch.dfr0_pmuver.unimp;
}
+static u8 perfmon_to_pmuver(u8 perfmon)
+{
+ switch (perfmon) {
+ case ID_DFR0_PERFMON_8_0:
+ return ID_AA64DFR0_EL1_PMUVer_IMP;
+ case ID_DFR0_PERFMON_IMP_DEF:
+ return ID_AA64DFR0_EL1_PMUVer_IMP_DEF;
Nit: Since IMP_DEF is 0xf for both PMUVER and PERFMON,
I think the 'default' can handle IMP_DEF (I have the same
comment for pmuver_to_perfmon in the patch-10).
It sure can, but IMP_DEF is special enough in its treatment
(we explicitly check this value in set_id_dfr0_el1()) that
it actually helps the reader to keep the explicit conversion
here.
+ default:
+ /* Anything ARMv8.1+ has the same value. For now. */
Nit: Shouldn't the comment also mention NI (and IMP_DEF) ?
(I have the same comment for pmuver_to_perfmon in the patch-10)
I can expand the comment to include NI.
Otherwise:
Reviewed-by: Reiji Watanabe <reijiw@xxxxxxxxxx>
Thanks,
M.
--
Jazz is not dead. It just smells funny...
