From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=217.140.101.70; helo=foss.arm.com; envelope-from=marc.zyngier@arm.com; receiver=edk2-devel@lists.01.org Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by ml01.01.org (Postfix) with ESMTP id 44491223FCF2F for ; Thu, 15 Mar 2018 03:33:56 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B199B80D; Thu, 15 Mar 2018 03:40:20 -0700 (PDT) Received: from [10.1.206.75] (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C33403F24A; Thu, 15 Mar 2018 03:40:19 -0700 (PDT) To: Ard Biesheuvel , edk2-devel@lists.01.org Cc: leif.lindholm@linaro.org, lersek@redhat.com, heyi.guo@linaro.org References: <20180315102826.10517-1-ard.biesheuvel@linaro.org> From: Marc Zyngier Organization: ARM Ltd Message-ID: Date: Thu, 15 Mar 2018 10:40:18 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180315102826.10517-1-ard.biesheuvel@linaro.org> Subject: Re: [PATCH] ArmPkg/TimerDxe: remove workaround for KVM timer handling X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 15 Mar 2018 10:33:57 -0000 Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit On 15/03/18 10:28, Ard Biesheuvel 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. > > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Ard Biesheuvel > --- > 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); > } > > Acked-by: Marc Zyngier M. -- Jazz is not dead. It just smells funny...