lwn.git/arch/riscv/kvm/vcpu_sbi_pmu.c, branch master

RISC-V: KVM: Implement get event info function

2025-09-16T06:19:31+00:00

The new get_event_info funciton allows the guest to query the presence of multiple events with single SBI call. Currently, the perf driver in linux guest invokes it for all the standard SBI PMU events. Support the SBI function implementation in KVM as well. Reviewed-by: Anup Patel Signed-off-by: Atish Patra Acked-by: Paul Walmsley Link: https://lore.kernel.org/r/20250909-pmu_event_info-v6-7-d8f80cacb884@rivosinc.com Signed-off-by: Anup Patel

RISC-V: KVM: Improve firmware counter read function

2024-04-26T07:43:54+00:00

Rename the function to indicate that it is meant for firmware counter read. While at it, add a range sanity check for it as well. Reviewed-by: Andrew Jones Signed-off-by: Atish Patra Reviewed-by: Anup Patel Link: https://lore.kernel.org/r/20240420151741.962500-17-atishp@rivosinc.com Signed-off-by: Anup Patel

RISC-V: KVM: Support 64 bit firmware counters on RV32

2024-04-26T07:43:52+00:00

The SBI v2.0 introduced a fw_read_hi function to read 64 bit firmware counters for RV32 based systems. Add infrastructure to support that. Reviewed-by: Andrew Jones Reviewed-by: Anup Patel Signed-off-by: Atish Patra Link: https://lore.kernel.org/r/20240420151741.962500-16-atishp@rivosinc.com Signed-off-by: Anup Patel

RISC-V: KVM: Implement SBI PMU Snapshot feature

2024-04-26T07:43:48+00:00

PMU Snapshot function allows to minimize the number of traps when the guest access configures/access the hpmcounters. If the snapshot feature is enabled, the hypervisor updates the shared memory with counter data and state of overflown counters. The guest can just read the shared memory instead of trap & emulate done by the hypervisor. This patch doesn't implement the counter overflow yet. Reviewed-by: Anup Patel Reviewed-by: Andrew Jones Signed-off-by: Atish Patra Link: https://lore.kernel.org/r/20240420151741.962500-14-atishp@rivosinc.com Signed-off-by: Anup Patel

RISC-V: KVM: No need to exit to the user space if perf event failed

2024-04-26T07:43:46+00:00

Currently, we return a linux error code if creating a perf event failed in kvm. That shouldn't be necessary as guest can continue to operate without perf profiling or profiling with firmware counters. Return appropriate SBI error code to indicate that PMU configuration failed. An error message in kvm already describes the reason for failure. Fixes: 0cb74b65d2e5 ("RISC-V: KVM: Implement perf support without sampling") Reviewed-by: Anup Patel Signed-off-by: Atish Patra Link: https://lore.kernel.org/r/20240420151741.962500-13-atishp@rivosinc.com Signed-off-by: Anup Patel

RISC-V: KVM: Add SBI PMU extension support

2023-02-07T15:05:53+00:00

SBI PMU extension allows KVM guests to configure/start/stop/query about the PMU counters in virtualized enviornment as well. In order to allow that, KVM implements the entire SBI PMU extension. Reviewed-by: Anup Patel Reviewed-by: Andrew Jones Signed-off-by: Atish Patra Signed-off-by: Anup Patel