While the spec doesn't state it, setting timecmp to UINT64_MAX is
another way to stop a timer, as it's considered setting the next
timer event to occur at infinity. And, even if the time CSR does
eventually reach UINT64_MAX, the very next tick will bring it back to
zero, once again less than timecmp. For this reason
riscv_timer_write_timecmp() special cases UINT64_MAX. However, if a
previously set timecmp has not yet expired, then setting timecmp to
UINT64_MAX to disable / stop it would not work, as the special case
left the previous QEMU timer active, which would then still deliver
an interrupt at that previous timecmp time. Ensure the stopped timer
will not still deliver an interrupt by also deleting the QEMU timer
in the UINT64_MAX special case.
Fixes: ae0edf2188 ("target/riscv: No need to re-start QEMU timer when timecmp == UINT64_MAX")
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240829084002.1805006-2-ajones@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Use CPURISCVState as argument directly in riscv_cpu_update_mip and
riscv_timer_write_timecmp, since type converts from CPURISCVState to
RISCVCPU in many caller of them and then back to CPURISCVState in them.
Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-Id: <20230309071329.45932-4-liweiwei@iscas.ac.cn>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The time CSR will wrap-around immediately after reaching UINT64_MAX
so we don't need to re-start QEMU timer when timecmp == UINT64_MAX
in riscv_timer_write_timecmp().
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20230120125950.2246378-4-apatel@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Instead of clearing mask in riscv_cpu_update_mip() for VSTIP, we
should call riscv_cpu_update_mip() with mask == 0 from timer_helper.c
for VSTIP.
Fixes: 3ec0fe18a3 ("target/riscv: Add vstimecmp suppor")
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20230120125950.2246378-3-apatel@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
vstimecmp CSR allows the guest OS or to program the next guest timer
interrupt directly. Thus, hypervisor no longer need to inject the
timer interrupt to the guest if vstimecmp is used. This was ratified
as a part of the Sstc extension.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220824221357.41070-4-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
stimecmp allows the supervisor mode to update stimecmp CSR directly
to program the next timer interrupt. This CSR is part of the Sstc
extension which was ratified recently.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220824221357.41070-3-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
