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LoongArch: KVM: Add PMU support for guest

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On LoongArch, the host and guest have their own PMU CSRs registers and
they share PMU hardware resources. A set of PMU CSRs consists of a CTRL
register and a CNTR register. We can set which PMU CSRs are used by the
guest by writing to the GCFG register [24:26] bits.

On KVM side:
- Save the host PMU CSRs into structure kvm_context.
- If the host supports the PMU feature.
  - When entering guest mode, save the host PMU CSRs and restore the guest PMU CSRs.
  - When exiting guest mode, save the guest PMU CSRs and restore the host PMU CSRs.

Reviewed-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Song Gao
2024-09-12 20:53:40 +08:00
committed by Huacai Chen
parent acc7f20d54
commit f4e40ea9f7
7 changed files with 205 additions and 3 deletions
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arch/loongarch/include/uapi/asm/kvm.h
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@@ -98,6 +98,7 @@ struct kvm_fpu {
#define KVM_LOONGARCH_VM_FEAT_X86BT 2
#define KVM_LOONGARCH_VM_FEAT_ARMBT 3
#define KVM_LOONGARCH_VM_FEAT_MIPSBT 4
#define KVM_LOONGARCH_VM_FEAT_PMU 5
/* Device Control API on vcpu fd */
#define KVM_LOONGARCH_VCPU_CPUCFG 0