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Date:   Mon, 21 Feb 2022 17:56:00 +0000
From:   Wei Liu <wei.liu@kernel.org>
To:     "Michael Kelley (LINUX)" <mikelley@microsoft.com>
Cc:     Boqun Feng <boqun.feng@gmail.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Wei Liu <wei.liu@kernel.org>,
        Sunil Muthuswamy <sunilmut@linux.microsoft.com>,
        KY Srinivasan <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Dexuan Cui <decui@microsoft.com>,
        Rob Herring <robh@kernel.org>,
        Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= <kw@linux.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH v2] PCI: hv: Avoid the retarget interrupt hypercall
 in irq_unmask() on ARM64
Message-ID: <20220221175600.gxbphsnbytgytcpz@liuwe-devbox-debian-v2>
References: <20220217034525.1687678-1-boqun.feng@gmail.com>
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On Thu, Feb 17, 2022 at 04:31:06PM +0000, Michael Kelley (LINUX) wrote:
> From: Boqun Feng <boqun.feng@gmail.com> Sent: Wednesday, February 16, 2022 7:45 PM
> > 
> > On ARM64 Hyper-V guests, SPIs are used for the interrupts of virtual PCI
> > devices, and SPIs can be managed directly via GICD registers. Therefore
> > the retarget interrupt hypercall is not needed on ARM64.
> > 
> > An arch-specific interface hv_arch_irq_unmask() is introduced to handle
> > the architecture level differences on this. For x86, the behavior
> > remains unchanged, while for ARM64 no hypercall is invoked when
> > unmasking an irq for virtual PCI devices.
> > 
> > Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> > ---
> > v1 -> v2:
> > 
> > *	Introduce arch-specific interface hv_arch_irq_unmask() as
> > 	suggested by Bjorn
> > 
> >  drivers/pci/controller/pci-hyperv.c | 233 +++++++++++++++-------------
> >  1 file changed, 122 insertions(+), 111 deletions(-)
> 
> Reviewed-by: Michael Kelley <mikelley@microsoft.com>

I expect this to go through the PCI tree. Let me know if I should pick
this up.

Thanks,
Wei.