On Fri, Dec 13, 2024 at 2:27 AM Atish Patra <atishp@xxxxxxxxxxxx> wrote:
>
> Currently, kvm doesn't delegate the few traps such as misaligned
> load/store, illegal instruction and load/store access faults because it
> is not expected to occur in the guest very frequent. Thus, kvm gets a
> chance to act upon it or collect statstics about it before redirecting
> the traps to the guest.
>
> We can collect both guest and host visible statistics during the traps.
> Enable them so that both guest and host can collect the stats about
> them if required.
s/We can collect .../Collect .../
>
> Signed-off-by: Atish Patra <atishp@xxxxxxxxxxxx>
Otherwise, it looks good to me.
Reviewed-by: Anup Patel <anup@xxxxxxxxxxxxxx>
Regards,
Anup
> ---
> arch/riscv/include/asm/kvm_host.h | 5 +++++
> arch/riscv/kvm/vcpu.c | 7 ++++++-
> arch/riscv/kvm/vcpu_exit.c | 5 +++++
> 3 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
> index 35eab6e0f4ae..cc33e35cd628 100644
> --- a/arch/riscv/include/asm/kvm_host.h
> +++ b/arch/riscv/include/asm/kvm_host.h
> @@ -87,6 +87,11 @@ struct kvm_vcpu_stat {
> u64 csr_exit_kernel;
> u64 signal_exits;
> u64 exits;
> + u64 instr_illegal_exits;
> + u64 load_misaligned_exits;
> + u64 store_misaligned_exits;
> + u64 load_access_exits;
> + u64 store_access_exits;
> };
>
> struct kvm_arch_memory_slot {
> diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
> index e048dcc6e65e..60d684c76c58 100644
> --- a/arch/riscv/kvm/vcpu.c
> +++ b/arch/riscv/kvm/vcpu.c
> @@ -34,7 +34,12 @@ const struct _kvm_stats_desc kvm_vcpu_stats_desc[] = {
> STATS_DESC_COUNTER(VCPU, csr_exit_user),
> STATS_DESC_COUNTER(VCPU, csr_exit_kernel),
> STATS_DESC_COUNTER(VCPU, signal_exits),
> - STATS_DESC_COUNTER(VCPU, exits)
> + STATS_DESC_COUNTER(VCPU, exits),
> + STATS_DESC_COUNTER(VCPU, instr_illegal_exits),
> + STATS_DESC_COUNTER(VCPU, load_misaligned_exits),
> + STATS_DESC_COUNTER(VCPU, store_misaligned_exits),
> + STATS_DESC_COUNTER(VCPU, load_access_exits),
> + STATS_DESC_COUNTER(VCPU, store_access_exits),
> };
>
> const struct kvm_stats_header kvm_vcpu_stats_header = {
> diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
> index acdcd619797e..6e0c18412795 100644
> --- a/arch/riscv/kvm/vcpu_exit.c
> +++ b/arch/riscv/kvm/vcpu_exit.c
> @@ -195,22 +195,27 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
> switch (trap->scause) {
> case EXC_INST_ILLEGAL:
> kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_ILLEGAL_INSN);
> + vcpu->stat.instr_illegal_exits++;
> ret = vcpu_redirect(vcpu, trap);
> break;
> case EXC_LOAD_MISALIGNED:
> kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_MISALIGNED_LOAD);
> + vcpu->stat.load_misaligned_exits++;
> ret = vcpu_redirect(vcpu, trap);
> break;
> case EXC_STORE_MISALIGNED:
> kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_MISALIGNED_STORE);
> + vcpu->stat.store_misaligned_exits++;
> ret = vcpu_redirect(vcpu, trap);
> break;
> case EXC_LOAD_ACCESS:
> kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_ACCESS_LOAD);
> + vcpu->stat.load_access_exits++;
> ret = vcpu_redirect(vcpu, trap);
> break;
> case EXC_STORE_ACCESS:
> kvm_riscv_vcpu_pmu_incr_fw(vcpu, SBI_PMU_FW_ACCESS_STORE);
> + vcpu->stat.store_access_exits++;
> ret = vcpu_redirect(vcpu, trap);
> break;
> case EXC_INST_ACCESS:
>
> --
> 2.34.1
>
