| Message ID | 20240426122913.3427983-3-peter.maydell@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | target/arm: Make the counter frequency default 1GHz for new CPUs, machines | expand |
On 26/4/24 14:29, Peter Maydell wrote: > Currently QEMU CPUs always run with a generic timer counter frequency > of 62.5MHz, but ARMv8.6 CPUs will run at 1GHz. For older versions of > the TF-A firmware that sbsa-ref runs, the frequency of the generic > timer is hardcoded into the firmware, and so if the CPU actually has > a different frequency then timers in the guest will be set > incorrectly. > > The default frequency used by the 'max' CPU is about to change, so > make the sbsa-ref board force the CPU frequency to the value which > the firmware expects. > > Newer versions of TF-A will read the frequency from the CPU's > CNTFRQ_EL0 register: > https://github.com/ARM-software/arm-trusted-firmware/commit/4c77fac98dac0bebc63798aae9101ac865b87148 > so in the longer term we could make this board use the 1GHz > frequency. We will need to make sure we update the binaries used > by our avocado test > Aarch64SbsarefMachine.test_sbsaref_alpine_linux_max_pauth_impdef > before we can do that. > > Signed-off-by: Peter Maydell <peter.maydell@linaro.org> > --- > I leave it up to the sbsa-ref maintainers exactly when they > want to shift to 1GHz (probably after a TF-A release with the fix?) > --- > hw/arm/sbsa-ref.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
W dniu 26.04.2024 o 14:29, Peter Maydell pisze: > The default frequency used by the 'max' CPU is about to change, so > make the sbsa-ref board force the CPU frequency to the value which > the firmware expects. > > Newer versions of TF-A will read the frequency from the CPU's > CNTFRQ_EL0 register: > https://github.com/ARM-software/arm-trusted-firmware/commit/4c77fac98dac0bebc63798aae9101ac865b87148 > so in the longer term we could make this board use the 1GHz > frequency. We will need to make sure we update the binaries used > by our avocado test > Aarch64SbsarefMachine.test_sbsaref_alpine_linux_max_pauth_impdef > before we can do that. > > Signed-off-by: Peter Maydell<peter.maydell@linaro.org> > --- > I leave it up to the sbsa-ref maintainers exactly when they > want to shift to 1GHz (probably after a TF-A release with the fix?) Reviewed-by: Marcin Juszkiewicz <marcin.juszkiewicz@linaro.org> TF-A 2.11 will be released in June. It will have several other improvements so I prefer to wait for it. We will have EDK2 202405 stable release then too which allow us to collect all changes we did during last half year (and maybe even those in progress). In meantime we go with 62.5 MHz frequency as it was before so no one will get "too fast wall clock" issue. Then, in a middle of June, new firmware will be built for QEMU CI and we will be able to move to 1 GHz by default and maybe add some other changes on top.
diff --git a/hw/arm/sbsa-ref.c b/hw/arm/sbsa-ref.c index f5709d6c141..36f6f717b4b 100644 --- a/hw/arm/sbsa-ref.c +++ b/hw/arm/sbsa-ref.c @@ -60,6 +60,19 @@ #define NUM_SMMU_IRQS 4 #define NUM_SATA_PORTS 6 +/* + * Generic timer frequency in Hz (which drives both the CPU generic timers + * and the SBSA watchdog-timer). Older versions of the TF-A firmware + * typically used with sbsa-ref (including the binaries in our Avocado test + * Aarch64SbsarefMachine.test_sbsaref_alpine_linux_max_pauth_impdef + * assume it is this value. + * + * TODO: this value is not architecturally correct for an Armv8.6 or + * better CPU, so we should move to 1GHz once the TF-A fix above has + * made it into a release and into our Avocado test. + */ +#define SBSA_GTIMER_HZ 62500000 + enum { SBSA_FLASH, SBSA_MEM, @@ -767,6 +780,8 @@ static void sbsa_ref_init(MachineState *machine) &error_abort); } + object_property_set_int(cpuobj, "cntfrq", SBSA_GTIMER_HZ, &error_abort); + object_property_set_link(cpuobj, "memory", OBJECT(sysmem), &error_abort);
Currently QEMU CPUs always run with a generic timer counter frequency of 62.5MHz, but ARMv8.6 CPUs will run at 1GHz. For older versions of the TF-A firmware that sbsa-ref runs, the frequency of the generic timer is hardcoded into the firmware, and so if the CPU actually has a different frequency then timers in the guest will be set incorrectly. The default frequency used by the 'max' CPU is about to change, so make the sbsa-ref board force the CPU frequency to the value which the firmware expects. Newer versions of TF-A will read the frequency from the CPU's CNTFRQ_EL0 register: https://github.com/ARM-software/arm-trusted-firmware/commit/4c77fac98dac0bebc63798aae9101ac865b87148 so in the longer term we could make this board use the 1GHz frequency. We will need to make sure we update the binaries used by our avocado test Aarch64SbsarefMachine.test_sbsaref_alpine_linux_max_pauth_impdef before we can do that. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- I leave it up to the sbsa-ref maintainers exactly when they want to shift to 1GHz (probably after a TF-A release with the fix?) --- hw/arm/sbsa-ref.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)