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>
2026-10-26 19:14:18 +00:00 · 2024-04-20 08:17:30 -07:00 · 2024-04-20 08:17:30 -07:00 · 16b0bde9a3
commit 16b0bde9a3
parent c2f41ddbcd
7 changed files with 93 additions and 8 deletions
--- a/arch/riscv/include/asm/csr.h
+++ b/arch/riscv/include/asm/csr.h
--- a/arch/riscv/include/asm/kvm_vcpu_pmu.h
+++ b/arch/riscv/include/asm/kvm_vcpu_pmu.h
--- a/arch/riscv/include/uapi/asm/kvm.h
+++ b/arch/riscv/include/uapi/asm/kvm.h
--- a/arch/riscv/kvm/aia.c
+++ b/arch/riscv/kvm/aia.c
--- a/arch/riscv/kvm/vcpu.c
+++ b/arch/riscv/kvm/vcpu.c
--- a/arch/riscv/kvm/vcpu_onereg.c
+++ b/arch/riscv/kvm/vcpu_onereg.c
--- a/arch/riscv/kvm/vcpu_pmu.c
+++ b/arch/riscv/kvm/vcpu_pmu.c