From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Christoffer Dall <christoffer.dall@arm.com>,
linux-kernel@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>,
Marc Zyngier <marc.zyngier@arm.com>,
Andre Przywara <andre.przywara@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] clocksource/arm_arch_timer: Store physical timer IRQ number for KVM on VHE
Date: Tue, 12 Feb 2019 10:15:22 +0100 [thread overview]
Message-ID: <49f5b2c1-8bbc-9475-e7bb-60857f622357@linaro.org> (raw)
In-Reply-To: <20190124134612.7487-1-christoffer.dall@arm.com>
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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prev parent reply other threads:[~2019-02-12 9:15 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-24 13:46 [PATCH] clocksource/arm_arch_timer: Store physical timer IRQ number for KVM on VHE Christoffer Dall
2019-02-12 9:15 ` Daniel Lezcano [this message]
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