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| author | Marc Zyngier <maz@kernel.org> | 2024-12-17 17:23:19 +0300 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2025-01-02 22:19:10 +0300 |
| commit | 0bc9a9e85fcf4ffb69846b961273fde4eb0d03ab (patch) | |
| tree | 4ac9a821ff5cad979e7844d54a955d5757fe81ab /arch/arm64/include/asm | |
| parent | d1e37a50e1d781201768c89314532f6ab87e5a42 (diff) | |
| download | linux-0bc9a9e85fcf4ffb69846b961273fde4eb0d03ab.tar.xz | |
KVM: arm64: Work around x1e's CNTVOFF_EL2 bogosity
It appears that on Qualcomm's x1e CPU, CNTVOFF_EL2 doesn't really
work, specially with HCR_EL2.E2H=1.
A non-zero offset results in a screaming virtual timer interrupt,
to the tune of a few 100k interrupts per second on a 4 vcpu VM.
This is also evidenced by this CPU's inability to correctly run
any of the timer selftests.
The only case this doesn't break is when this register is set to 0,
which breaks VM migration.
When HCR_EL2.E2H=0, the timer seems to behave normally, and does
not result in an interrupt storm.
As a workaround, use the fact that this CPU implements FEAT_ECV,
and trap all accesses to the virtual timer and counter, keeping
CNTVOFF_EL2 set to zero, and emulate accesses to CVAL/TVAL/CTL
and the counter itself, fixing up the timer to account for the
missing offset.
And if you think this is disgusting, you'd probably be right.
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241217142321.763801-12-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
Diffstat (limited to 'arch/arm64/include/asm')
| -rw-r--r-- | arch/arm64/include/asm/cputype.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h index 488f8e751349..6f3f4142e214 100644 --- a/arch/arm64/include/asm/cputype.h +++ b/arch/arm64/include/asm/cputype.h @@ -122,6 +122,7 @@ #define QCOM_CPU_PART_KRYO_3XX_SILVER 0x803 #define QCOM_CPU_PART_KRYO_4XX_GOLD 0x804 #define QCOM_CPU_PART_KRYO_4XX_SILVER 0x805 +#define QCOM_CPU_PART_ORYON_X1 0x001 #define NVIDIA_CPU_PART_DENVER 0x003 #define NVIDIA_CPU_PART_CARMEL 0x004 @@ -198,6 +199,7 @@ #define MIDR_QCOM_KRYO_3XX_SILVER MIDR_CPU_MODEL(ARM_CPU_IMP_QCOM, QCOM_CPU_PART_KRYO_3XX_SILVER) #define MIDR_QCOM_KRYO_4XX_GOLD MIDR_CPU_MODEL(ARM_CPU_IMP_QCOM, QCOM_CPU_PART_KRYO_4XX_GOLD) #define MIDR_QCOM_KRYO_4XX_SILVER MIDR_CPU_MODEL(ARM_CPU_IMP_QCOM, QCOM_CPU_PART_KRYO_4XX_SILVER) +#define MIDR_QCOM_ORYON_X1 MIDR_CPU_MODEL(ARM_CPU_IMP_QCOM, QCOM_CPU_PART_ORYON_X1) #define MIDR_NVIDIA_DENVER MIDR_CPU_MODEL(ARM_CPU_IMP_NVIDIA, NVIDIA_CPU_PART_DENVER) #define MIDR_NVIDIA_CARMEL MIDR_CPU_MODEL(ARM_CPU_IMP_NVIDIA, NVIDIA_CPU_PART_CARMEL) #define MIDR_FUJITSU_A64FX MIDR_CPU_MODEL(ARM_CPU_IMP_FUJITSU, FUJITSU_CPU_PART_A64FX) |