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| author | Atish Patra <atishp@rivosinc.com> | 2024-04-20 18:17:30 +0300 |
|---|---|---|
| committer | Anup Patel <anup@brainfault.org> | 2024-04-26 10:43:50 +0300 |
| commit | 16b0bde9a37c0af404318ca3cf64a11edccb8777 (patch) | |
| tree | 15b25401fd17b13b7f3087854c055d6de782bcd1 /arch/riscv/kvm/vcpu_onereg.c | |
| parent | c2f41ddbcdd75689d9f512638a40263e3127be93 (diff) | |
| download | linux-16b0bde9a37c0af404318ca3cf64a11edccb8777.tar.xz | |
RISC-V: KVM: Add perf sampling support for guests
KVM enables perf for guest via counter virtualization. However, the
sampling can not be supported as there is no mechanism to enabled
trap/emulate scountovf in ISA yet. Rely on the SBI PMU snapshot
to provide the counter overflow data via the shared memory.
In case of sampling event, the host first sets the guest's LCOFI
interrupt and injects to the guest via irq filtering mechanism defined
in AIA specification. Thus, ssaia must be enabled in the host in order
to use perf sampling in the guest. No other AIA dependency w.r.t kernel
is required.
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20240420151741.962500-15-atishp@rivosinc.com
Signed-off-by: Anup Patel <anup@brainfault.org>
Diffstat (limited to 'arch/riscv/kvm/vcpu_onereg.c')
| -rw-r--r-- | arch/riscv/kvm/vcpu_onereg.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c index 994adc26db4b..c676275ea0a0 100644 --- a/arch/riscv/kvm/vcpu_onereg.c +++ b/arch/riscv/kvm/vcpu_onereg.c @@ -36,6 +36,7 @@ static const unsigned long kvm_isa_ext_arr[] = { /* Multi letter extensions (alphabetically sorted) */ KVM_ISA_EXT_ARR(SMSTATEEN), KVM_ISA_EXT_ARR(SSAIA), + KVM_ISA_EXT_ARR(SSCOFPMF), KVM_ISA_EXT_ARR(SSTC), KVM_ISA_EXT_ARR(SVINVAL), KVM_ISA_EXT_ARR(SVNAPOT), @@ -99,6 +100,9 @@ static bool kvm_riscv_vcpu_isa_enable_allowed(unsigned long ext) switch (ext) { case KVM_RISCV_ISA_EXT_H: return false; + case KVM_RISCV_ISA_EXT_SSCOFPMF: + /* Sscofpmf depends on interrupt filtering defined in ssaia */ + return __riscv_isa_extension_available(NULL, RISCV_ISA_EXT_SSAIA); case KVM_RISCV_ISA_EXT_V: return riscv_v_vstate_ctrl_user_allowed(); default: @@ -116,6 +120,8 @@ static bool kvm_riscv_vcpu_isa_disable_allowed(unsigned long ext) case KVM_RISCV_ISA_EXT_C: case KVM_RISCV_ISA_EXT_I: case KVM_RISCV_ISA_EXT_M: + /* There is not architectural config bit to disable sscofpmf completely */ + case KVM_RISCV_ISA_EXT_SSCOFPMF: case KVM_RISCV_ISA_EXT_SSTC: case KVM_RISCV_ISA_EXT_SVINVAL: case KVM_RISCV_ISA_EXT_SVNAPOT: |