On Fri, Apr 11, 2025 at 8:03 AM Rob Herring robh@kernel.org wrote:
On Thu, Apr 10, 2025 at 11:24 PM Anshuman Khandual anshuman.khandual@arm.com wrote:
On 4/10/25 22:20, Rob Herring wrote:
On Wed, Apr 9, 2025 at 10:55 PM Anshuman Khandual anshuman.khandual@arm.com wrote:
From: "Rob Herring (Arm)" robh@kernel.org
Armv8.9/9.4 PMUv3.9 adds per counter EL0 access controls. Per counter access is enabled with the UEN bit in PMUSERENR_EL1 register. Individual counters are enabled/disabled in the PMUACR_EL1 register. When UEN is set, the CR/ER bits control EL0 write access and must be set to disable write access.
With the access controls, the clearing of unused counters can be skipped.
KVM also configures PMUSERENR_EL1 in order to trap to EL2. UEN does not need to be set for it since only PMUv3.5 is exposed to guests.
Signed-off-by: Rob Herring (Arm) robh@kernel.org Link: https://lore.kernel.org/r/20241002184326.1105499-1-robh@kernel.org Signed-off-by: Will Deacon will@kernel.org [cherry picked from commit 0bbff9ed81654d5f06bfca484681756ee407f924] Signed-off-by: Anshuman Khandual anshuman.khandual@arm.com
This one doesn't belong in 6.12. It's a feature that landed in 6.13. It's only the fixed instruction counter support that landed in 6.12.
Are you suggesting that this patch is not required for 6.12.y backport ?
Yes.
We need this commit for ID_AA64DFR0_EL1_PMUVer_V3P9 definition. Should this change be added in the last commit itself in the series instead ?
Ah, that's unfortunate. I suppose adding the hunk to the last commit is the easiest. Not sure what the preference would be here.
You could also change the comparison from <3.9 to <=3.8 and avoid needing the definition.
Rob