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| author | Marc Zyngier <maz@kernel.org> | 2019-10-02 12:06:12 +0300 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2019-10-15 14:26:09 +0300 |
| commit | f226650494c6aa87526d12135b7de8b8c074f3de (patch) | |
| tree | 1c00f90dac02fdb1240153bab7a9faa8565aa52a /arch/arm64/include/asm/kvm_host.h | |
| parent | 4f5cafb5cb8471e54afdc9054d973535614f7675 (diff) | |
| download | linux-f226650494c6aa87526d12135b7de8b8c074f3de.tar.xz | |
arm64: Relax ICC_PMR_EL1 accesses when ICC_CTLR_EL1.PMHE is clear
The GICv3 architecture specification is incredibly misleading when it
comes to PMR and the requirement for a DSB. It turns out that this DSB
is only required if the CPU interface sends an Upstream Control
message to the redistributor in order to update the RD's view of PMR.
This message is only sent when ICC_CTLR_EL1.PMHE is set, which isn't
the case in Linux. It can still be set from EL3, so some special care
is required. But the upshot is that in the (hopefuly large) majority
of the cases, we can drop the DSB altogether.
This relies on a new static key being set if the boot CPU has PMHE
set. The drawback is that this static key has to be exported to
modules.
Cc: Will Deacon <will@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/kvm_host.h')
| -rw-r--r-- | arch/arm64/include/asm/kvm_host.h | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index f656169db8c3..5ecb091c8576 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -600,8 +600,7 @@ static inline void kvm_arm_vhe_guest_enter(void) * local_daif_mask() already sets GIC_PRIO_PSR_I_SET, we just need a * dsb to ensure the redistributor is forwards EL2 IRQs to the CPU. */ - if (system_uses_irq_prio_masking()) - dsb(sy); + pmr_sync(); } static inline void kvm_arm_vhe_guest_exit(void) |