From: "Philippe Mathieu-Daudé" <philmd@linaro.org>
To: Andrew Jones <ajones@ventanamicro.com>,
Yong-Xuan Wang <yongxuan.wang@sifive.com>
Cc: qemu-devel@nongnu.org, qemu-riscv@nongnu.org,
greentime.hu@sifive.com, vincent.chen@sifive.com,
frank.chang@sifive.com, jim.shu@sifive.com,
Palmer Dabbelt <palmer@dabbelt.com>,
Alistair Francis <alistair.francis@wdc.com>,
Bin Meng <bin.meng@windriver.com>,
Weiwei Li <liwei1518@gmail.com>,
Daniel Henrique Barboza <dbarboza@ventanamicro.com>,
Liu Zhiwei <zhiwei_liu@linux.alibaba.com>
Subject: Re: [PATCH 1/1] target/riscv/kvm: fix timebase-frequency when using KVM acceleration
Date: Wed, 13 Mar 2024 11:24:58 +0100 [thread overview]
Message-ID: <b24dead7-b178-452c-ad76-05e4bc86ce79@linaro.org> (raw)
In-Reply-To: <20240313-d11a0490609909bd354f01b2@orel>
On 13/3/24 09:56, Andrew Jones wrote:
> On Wed, Mar 13, 2024 at 04:13:57PM +0800, Yong-Xuan Wang wrote:
>> The timebase-frequency of guest OS should be the same with host
>> machine. The timebase-frequency value in DTS should be got from
>> hypervisor when using KVM acceleration.
>>
>> Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
>> ---
>> hw/riscv/virt.c | 11 +++++++++--
>> target/riscv/kvm/kvm-cpu.c | 9 +++++++++
>> target/riscv/kvm/kvm_riscv.h | 13 +++++++++++++
>> 3 files changed, 31 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
>> index a094af97c32a..a7ed7fa13010 100644
>> --- a/hw/riscv/virt.c
>> +++ b/hw/riscv/virt.c
>> @@ -710,8 +710,15 @@ static void create_fdt_sockets(RISCVVirtState *s, const MemMapEntry *memmap,
>> int socket_count = riscv_socket_count(ms);
>>
>> qemu_fdt_add_subnode(ms->fdt, "/cpus");
>> - qemu_fdt_setprop_cell(ms->fdt, "/cpus", "timebase-frequency",
Alternatively:
kvm_enabled() ?
kvm_riscv_get_timebase_frequency(first_cpu) :
>> - RISCV_ACLINT_DEFAULT_TIMEBASE_FREQ);
>> +
>> + if (kvm_enabled()) {
>> + qemu_fdt_setprop_cell(ms->fdt, "/cpus", "timebase-frequency",
>> + kvm_riscv_get_timebase_frequency(first_cpu));
>> + } else {
>> + qemu_fdt_setprop_cell(ms->fdt, "/cpus", "timebase-frequency",
>> + RISCV_ACLINT_DEFAULT_TIMEBASE_FREQ);
>> + }
>> +
>> qemu_fdt_setprop_cell(ms->fdt, "/cpus", "#size-cells", 0x0);
>> qemu_fdt_setprop_cell(ms->fdt, "/cpus", "#address-cells", 0x1);
>> qemu_fdt_add_subnode(ms->fdt, "/cpus/cpu-map");
>> diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
>> index c7afdb1e81b7..bbb115eaa867 100644
>> --- a/target/riscv/kvm/kvm-cpu.c
>> +++ b/target/riscv/kvm/kvm-cpu.c
>> @@ -739,6 +739,15 @@ static void kvm_riscv_put_regs_timer(CPUState *cs)
>> env->kvm_timer_dirty = false;
>> }
>>
>> +uint64_t kvm_riscv_get_timebase_frequency(CPUState *cs)
>> +{
>> + uint64_t reg;
>> +
>> + KVM_RISCV_GET_TIMER(cs, frequency, reg);
>> +
>> + return reg;
>> +}
>> +
>> static int kvm_riscv_get_regs_vector(CPUState *cs)
>> {
>> RISCVCPU *cpu = RISCV_CPU(cs);
>> diff --git a/target/riscv/kvm/kvm_riscv.h b/target/riscv/kvm/kvm_riscv.h
>> index 4bd98fddc776..130a4bde0480 100644
>> --- a/target/riscv/kvm/kvm_riscv.h
>> +++ b/target/riscv/kvm/kvm_riscv.h
>> @@ -29,4 +29,17 @@ void riscv_kvm_aplic_request(void *opaque, int irq, int level);
>> int kvm_riscv_sync_mpstate_to_kvm(RISCVCPU *cpu, int state);
>> void riscv_kvm_cpu_finalize_features(RISCVCPU *cpu, Error **errp);
>>
>> +#ifdef CONFIG_KVM
>> +
>> +uint64_t kvm_riscv_get_timebase_frequency(CPUState *cs);
>> +
>> +#else
>> +
>> +static inline uint64_t kvm_riscv_get_timebase_frequency(CPUState *cs)
>> +{
>> + g_assert_not_reached();
>> +}
>> +
>> +#endif
>> +
>
> I think we've decided we don't need stubs like these since kvm_riscv_*
> functions should always be called within 'if (kvm_enabled())' blocks (as
> you have above), and then we leave it to the compile testing to point
> out kvm function calls without kvm_enabled().
Yes please!
>
>> #endif
>> --
>> 2.17.1
prev parent reply other threads:[~2024-03-13 10:26 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-13 8:13 [PATCH 1/1] target/riscv/kvm: fix timebase-frequency when using KVM acceleration Yong-Xuan Wang
2024-03-13 8:56 ` Andrew Jones
2024-03-13 10:24 ` Philippe Mathieu-Daudé [this message]
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