ArmPkg/Drivers/TimerDxe/TimerDxe.c | 1 - ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c | 10 ---------- 2 files changed, 11 deletions(-)
When we first ported EDK2 to KVM/arm, we implemented a workaround for
the quirky timer handling on the KVM side. This has been fixed in
Linux commit f120cd6533d2 ("KVM: arm/arm64: timer: Allow the timer to
control the active state") dated 23 June 2014, which was incorporated
into Linux release 4.3.
So almost 4 years later, it should be safe to drop this workaround on
the EDK2 side.
This reverts commit b1a633434ddc.
Cc: cross-distro@lists.linaro.org
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Acked-by: Laszlo Ersek <lersek@redhat.com>
---
v2: add acks
Note to cross-distro readers: this means guest firmware built with this patch
will not work on KVM/ARM hosts using kernel v4.2 or earlier.
ArmPkg/Drivers/TimerDxe/TimerDxe.c | 1 -
ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c | 10 ----------
2 files changed, 11 deletions(-)
diff --git a/ArmPkg/Drivers/TimerDxe/TimerDxe.c b/ArmPkg/Drivers/TimerDxe/TimerDxe.c
index a3202fa056f3..bd616d2efc73 100644
--- a/ArmPkg/Drivers/TimerDxe/TimerDxe.c
+++ b/ArmPkg/Drivers/TimerDxe/TimerDxe.c
@@ -337,7 +337,6 @@ TimerInterruptHandler (
// Set next compare value
ArmGenericTimerSetCompareVal (CompareValue);
- ArmGenericTimerEnableTimer ();
ArmInstructionSynchronizationBarrier ();
}
diff --git a/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c b/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c
index 69a4ceb62db6..c941895a3574 100644
--- a/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c
+++ b/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c
@@ -26,16 +26,6 @@ ArmGenericTimerEnableTimer (
TimerCtrlReg = ArmReadCntvCtl ();
TimerCtrlReg |= ARM_ARCH_TIMER_ENABLE;
-
- //
- // When running under KVM, we need to unmask the interrupt on the timer side
- // as KVM will mask it when servicing the interrupt at the hypervisor level
- // and delivering the virtual timer interrupt to the guest. Otherwise, the
- // interrupt will fire again, trapping into the hypervisor again, etc. etc.
- // This is scheduled to be fixed on the KVM side, but there is no harm in
- // leaving this in once KVM gets fixed.
- //
- TimerCtrlReg &= ~ARM_ARCH_TIMER_IMASK;
ArmWriteCntvCtl (TimerCtrlReg);
}
--
2.17.0
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On 17 April 2018 at 08:03, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> When we first ported EDK2 to KVM/arm, we implemented a workaround for
> the quirky timer handling on the KVM side. This has been fixed in
> Linux commit f120cd6533d2 ("KVM: arm/arm64: timer: Allow the timer to
> control the active state") dated 23 June 2014, which was incorporated
> into Linux release 4.3.
>
> So almost 4 years later, it should be safe to drop this workaround on
> the EDK2 side.
>
> This reverts commit b1a633434ddc.
>
> Cc: cross-distro@lists.linaro.org
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Acked-by: Marc Zyngier <marc.zyngier@arm.com>
> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
> Acked-by: Laszlo Ersek <lersek@redhat.com>
Pushed as 411a373ed6426fb1bff253905b6a59ada44e18ad
Thanks all
> ---
> v2: add acks
>
> Note to cross-distro readers: this means guest firmware built with this patch
> will not work on KVM/ARM hosts using kernel v4.2 or earlier.
>
> ArmPkg/Drivers/TimerDxe/TimerDxe.c | 1 -
> ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c | 10 ----------
> 2 files changed, 11 deletions(-)
>
> diff --git a/ArmPkg/Drivers/TimerDxe/TimerDxe.c b/ArmPkg/Drivers/TimerDxe/TimerDxe.c
> index a3202fa056f3..bd616d2efc73 100644
> --- a/ArmPkg/Drivers/TimerDxe/TimerDxe.c
> +++ b/ArmPkg/Drivers/TimerDxe/TimerDxe.c
> @@ -337,7 +337,6 @@ TimerInterruptHandler (
>
> // Set next compare value
> ArmGenericTimerSetCompareVal (CompareValue);
> - ArmGenericTimerEnableTimer ();
> ArmInstructionSynchronizationBarrier ();
> }
>
> diff --git a/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c b/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c
> index 69a4ceb62db6..c941895a3574 100644
> --- a/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c
> +++ b/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c
> @@ -26,16 +26,6 @@ ArmGenericTimerEnableTimer (
>
> TimerCtrlReg = ArmReadCntvCtl ();
> TimerCtrlReg |= ARM_ARCH_TIMER_ENABLE;
> -
> - //
> - // When running under KVM, we need to unmask the interrupt on the timer side
> - // as KVM will mask it when servicing the interrupt at the hypervisor level
> - // and delivering the virtual timer interrupt to the guest. Otherwise, the
> - // interrupt will fire again, trapping into the hypervisor again, etc. etc.
> - // This is scheduled to be fixed on the KVM side, but there is no harm in
> - // leaving this in once KVM gets fixed.
> - //
> - TimerCtrlReg &= ~ARM_ARCH_TIMER_IMASK;
> ArmWriteCntvCtl (TimerCtrlReg);
> }
>
> --
> 2.17.0
>
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Hi Ard,
Sorry for the late reply.
On 19/04/18 09:16, Ard Biesheuvel wrote:
> On 17 April 2018 at 08:03, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>> When we first ported EDK2 to KVM/arm, we implemented a workaround for
>> the quirky timer handling on the KVM side. This has been fixed in
>> Linux commit f120cd6533d2 ("KVM: arm/arm64: timer: Allow the timer to
>> control the active state") dated 23 June 2014, which was incorporated
>> into Linux release 4.3.
>>
>> So almost 4 years later, it should be safe to drop this workaround on
>> the EDK2 side.
>>
>> This reverts commit b1a633434ddc.
>>
>> Cc: cross-distro@lists.linaro.org
>> Contributed-under: TianoCore Contribution Agreement 1.1
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> Acked-by: Marc Zyngier <marc.zyngier@arm.com>
>> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
>> Acked-by: Laszlo Ersek <lersek@redhat.com>
>
> Pushed as 411a373ed6426fb1bff253905b6a59ada44e18ad
While this was added for KVM, I believe that code is also needed by Xen.
Indeed before injecting the interrupt the hypervisor will mask the
interrupt.
So would it be possible to revert that patch?
Cheers,
>
> Thanks all
>
>> ---
>> v2: add acks
>>
>> Note to cross-distro readers: this means guest firmware built with this patch
>> will not work on KVM/ARM hosts using kernel v4.2 or earlier.
>>
>> ArmPkg/Drivers/TimerDxe/TimerDxe.c | 1 -
>> ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c | 10 ----------
>> 2 files changed, 11 deletions(-)
>>
>> diff --git a/ArmPkg/Drivers/TimerDxe/TimerDxe.c b/ArmPkg/Drivers/TimerDxe/TimerDxe.c
>> index a3202fa056f3..bd616d2efc73 100644
>> --- a/ArmPkg/Drivers/TimerDxe/TimerDxe.c
>> +++ b/ArmPkg/Drivers/TimerDxe/TimerDxe.c
>> @@ -337,7 +337,6 @@ TimerInterruptHandler (
>>
>> // Set next compare value
>> ArmGenericTimerSetCompareVal (CompareValue);
>> - ArmGenericTimerEnableTimer ();
>> ArmInstructionSynchronizationBarrier ();
>> }
>>
>> diff --git a/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c b/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c
>> index 69a4ceb62db6..c941895a3574 100644
>> --- a/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c
>> +++ b/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c
>> @@ -26,16 +26,6 @@ ArmGenericTimerEnableTimer (
>>
>> TimerCtrlReg = ArmReadCntvCtl ();
>> TimerCtrlReg |= ARM_ARCH_TIMER_ENABLE;
>> -
>> - //
>> - // When running under KVM, we need to unmask the interrupt on the timer side
>> - // as KVM will mask it when servicing the interrupt at the hypervisor level
>> - // and delivering the virtual timer interrupt to the guest. Otherwise, the
>> - // interrupt will fire again, trapping into the hypervisor again, etc. etc.
>> - // This is scheduled to be fixed on the KVM side, but there is no harm in
>> - // leaving this in once KVM gets fixed.
>> - //
>> - TimerCtrlReg &= ~ARM_ARCH_TIMER_IMASK;
>> ArmWriteCntvCtl (TimerCtrlReg);
>> }
>>
>> --
>> 2.17.0
>>
> _______________________________________________
> cross-distro mailing list
> cross-distro@lists.linaro.org
> https://lists.linaro.org/mailman/listinfo/cross-distro
>
--
Julien Grall
_______________________________________________
edk2-devel mailing list
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https://lists.01.org/mailman/listinfo/edk2-devel
On 19 April 2018 at 16:23, Julien Grall <julien.grall@arm.com> wrote:
> Hi Ard,
>
> Sorry for the late reply.
>
> On 19/04/18 09:16, Ard Biesheuvel wrote:
>>
>> On 17 April 2018 at 08:03, Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> wrote:
>>>
>>> When we first ported EDK2 to KVM/arm, we implemented a workaround for
>>> the quirky timer handling on the KVM side. This has been fixed in
>>> Linux commit f120cd6533d2 ("KVM: arm/arm64: timer: Allow the timer to
>>> control the active state") dated 23 June 2014, which was incorporated
>>> into Linux release 4.3.
>>>
>>> So almost 4 years later, it should be safe to drop this workaround on
>>> the EDK2 side.
>>>
>>> This reverts commit b1a633434ddc.
>>>
>>> Cc: cross-distro@lists.linaro.org
>>> Contributed-under: TianoCore Contribution Agreement 1.1
>>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>>> Acked-by: Marc Zyngier <marc.zyngier@arm.com>
>>> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
>>> Acked-by: Laszlo Ersek <lersek@redhat.com>
>>
>>
>> Pushed as 411a373ed6426fb1bff253905b6a59ada44e18ad
>
>
> While this was added for KVM, I believe that code is also needed by Xen.
> Indeed before injecting the interrupt the hypervisor will mask the
> interrupt.
>
> So would it be possible to revert that patch?
>
Given that this is now a Xen-only quirk, I'd rather work around it by
creating a separate ArmGenericTimerCounterLib implementation for Xen.
I will try to put something together beginning of next week.
_______________________________________________
edk2-devel mailing list
edk2-devel@lists.01.org
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On 19/04/18 15:34, Ard Biesheuvel wrote:
> On 19 April 2018 at 16:23, Julien Grall <julien.grall@arm.com> wrote:
>> Hi Ard,
>>
>> Sorry for the late reply.
>>
>> On 19/04/18 09:16, Ard Biesheuvel wrote:
>>>
>>> On 17 April 2018 at 08:03, Ard Biesheuvel <ard.biesheuvel@linaro.org>
>>> wrote:
>>>>
>>>> When we first ported EDK2 to KVM/arm, we implemented a workaround for
>>>> the quirky timer handling on the KVM side. This has been fixed in
>>>> Linux commit f120cd6533d2 ("KVM: arm/arm64: timer: Allow the timer to
>>>> control the active state") dated 23 June 2014, which was incorporated
>>>> into Linux release 4.3.
>>>>
>>>> So almost 4 years later, it should be safe to drop this workaround on
>>>> the EDK2 side.
>>>>
>>>> This reverts commit b1a633434ddc.
>>>>
>>>> Cc: cross-distro@lists.linaro.org
>>>> Contributed-under: TianoCore Contribution Agreement 1.1
>>>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>>>> Acked-by: Marc Zyngier <marc.zyngier@arm.com>
>>>> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
>>>> Acked-by: Laszlo Ersek <lersek@redhat.com>
>>>
>>>
>>> Pushed as 411a373ed6426fb1bff253905b6a59ada44e18ad
>>
>>
>> While this was added for KVM, I believe that code is also needed by Xen.
>> Indeed before injecting the interrupt the hypervisor will mask the
>> interrupt.
>>
>> So would it be possible to revert that patch?
>>
>
> Given that this is now a Xen-only quirk, I'd rather work around it by
> creating a separate ArmGenericTimerCounterLib implementation for Xen.
That would work for me.
>
> I will try to put something together beginning of next week.
I am happy to test it.
Cheers,
--
Julien Grall
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