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 <ajones@ventanamicro.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20240420151741.962500-17-atishp@rivosinc.com
Signed-off-by: Anup Patel <anup@brainfault.org>
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 <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20240420151741.962500-16-atishp@rivosinc.com
Signed-off-by: Anup Patel <anup@brainfault.org>
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 <anup@brainfault.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20240420151741.962500-14-atishp@rivosinc.com
Signed-off-by: Anup Patel <anup@brainfault.org>
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: 0cb74b65d2 ("RISC-V: KVM: Implement perf support without sampling")
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20240420151741.962500-13-atishp@rivosinc.com
Signed-off-by: Anup Patel <anup@brainfault.org>
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 <anup@brainfault.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
