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>
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>
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>
SBI PMU extension defines a set of firmware events which can provide
useful information to guests about the number of SBI calls. As
hypervisor implements the SBI PMU extension, these firmware events
correspond to ecall invocations between VS->HS mode. All other firmware
events will always report zero if monitored as KVM doesn't implement them.
This patch adds all the infrastructure required to support firmware
events.
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>
As the KVM guests only see the virtual PMU counters, all hpmcounter
access should trap and KVM emulates the read access on behalf of guests.
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>
This patch only adds barebone structure of perf implementation. Most
of the function returns zero at this point and will be implemented
fully in the future.
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>
