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SubjectRe: [PATCH] clocksource/arm_arch_timer: Store physical timer IRQ number for KVM on VHE
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On 24/01/2019 14:46, Christoffer Dall wrote:
> From: Andre Przywara <andre.przywara@arm.com>
>
> A host running in VHE mode gets the EL2 physical timer as its time
> source (accessed using the EL1 sysreg accessors, which get re-directed
> to the EL2 sysregs by VHE).
>
> The EL1 physical timer remains unused by the host kernel, allowing us to
> pass that on directly to a KVM guest and saves us from emulating this
> timer for the guest on VHE systems.
>
> Store the EL1 Physical Timer's IRQ number in
> struct arch_timer_kvm_info on VHE systems to allow KVM to use it.
>
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
> ---
> Patches in preparation for nested virtualization on KVM/Arm depend on this
> change, so we would like to merge this via the kvmarm tree or have a stable
> branch including this patch.
>
> Please let us know your preference. Thanks.

Hi Christopher,

sorry for the delay. I'm fine if you want to take it through your tree.

Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>



> drivers/clocksource/arm_arch_timer.c | 11 +++++++++--
> include/clocksource/arm_arch_timer.h | 1 +
> 2 files changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
> index 9a7d4dc00b6e..b9243e2328b4 100644
> --- a/drivers/clocksource/arm_arch_timer.c
> +++ b/drivers/clocksource/arm_arch_timer.c
> @@ -1206,6 +1206,13 @@ static enum arch_timer_ppi_nr __init arch_timer_select_ppi(void)
> return ARCH_TIMER_PHYS_SECURE_PPI;
> }
>
> +static void __init arch_timer_populate_kvm_info(void)
> +{
> + arch_timer_kvm_info.virtual_irq = arch_timer_ppi[ARCH_TIMER_VIRT_PPI];
> + if (is_kernel_in_hyp_mode())
> + arch_timer_kvm_info.physical_irq = arch_timer_ppi[ARCH_TIMER_PHYS_NONSECURE_PPI];
> +}
> +
> static int __init arch_timer_of_init(struct device_node *np)
> {
> int i, ret;
> @@ -1220,7 +1227,7 @@ static int __init arch_timer_of_init(struct device_node *np)
> for (i = ARCH_TIMER_PHYS_SECURE_PPI; i < ARCH_TIMER_MAX_TIMER_PPI; i++)
> arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
>
> - arch_timer_kvm_info.virtual_irq = arch_timer_ppi[ARCH_TIMER_VIRT_PPI];
> + arch_timer_populate_kvm_info();
>
> rate = arch_timer_get_cntfrq();
> arch_timer_of_configure_rate(rate, np);
> @@ -1550,7 +1557,7 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table)
> arch_timer_ppi[ARCH_TIMER_HYP_PPI] =
> acpi_gtdt_map_ppi(ARCH_TIMER_HYP_PPI);
>
> - arch_timer_kvm_info.virtual_irq = arch_timer_ppi[ARCH_TIMER_VIRT_PPI];
> + arch_timer_populate_kvm_info();
>
> /*
> * When probing via ACPI, we have no mechanism to override the sysreg
> diff --git a/include/clocksource/arm_arch_timer.h b/include/clocksource/arm_arch_timer.h
> index 349e5957c949..702967d996bb 100644
> --- a/include/clocksource/arm_arch_timer.h
> +++ b/include/clocksource/arm_arch_timer.h
> @@ -74,6 +74,7 @@ enum arch_timer_spi_nr {
> struct arch_timer_kvm_info {
> struct timecounter timecounter;
> int virtual_irq;
> + int physical_irq;
> };
>
> struct arch_timer_mem_frame {
>


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