KVM: arm64: PMU: Fix GET_ONE_REG for vPMC regs to return the current value

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commit 9228b26194 upstream.

Have KVM_GET_ONE_REG for vPMU counter (vPMC) registers (PMCCNTR_EL0
and PMEVCNTR<n>_EL0) return the sum of the register value in the sysreg
file and the current perf event counter value.

Values of vPMC registers are saved in sysreg files on certain occasions.
These saved values don't represent the current values of the vPMC
registers if the perf events for the vPMCs count events after the save.
The current values of those registers are the sum of the sysreg file
value and the current perf event counter value.  But, when userspace
reads those registers (using KVM_GET_ONE_REG), KVM returns the sysreg
file value to userspace (not the sum value).

Fix this to return the sum value for KVM_GET_ONE_REG.

Fixes: 051ff581ce ("arm64: KVM: Add access handler for event counter register")
Cc: stable@vger.kernel.org
Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Reiji Watanabe <reijiw@google.com>
Link: https://lore.kernel.org/r/20230313033208.1475499-1-reijiw@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Reiji Watanabe 2023-03-12 20:32:08 -07:00 • committed by Greg Kroah-Hartman

parent fcf712b4e5

commit 051e660c81

1 changed files with 19 additions and 2 deletions

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arch/arm64/kvm/sys_regs.c

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