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From:   Dexuan Cui <decui@microsoft.com>
To:     Dexuan Cui <decui@microsoft.com>,
        "wei.liu@kernel.org" <wei.liu@kernel.org>,
        KY Srinivasan <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        "lorenzo.pieralisi@arm.com" <lorenzo.pieralisi@arm.com>,
        "bhelgaas@google.com" <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>,
        Michael Kelley <mikelley@microsoft.com>
CC:     Jake Oshins <jakeo@microsoft.com>
Subject: RE: [PATCH v2] PCI: hv: Fix hibernation in case interrupts are not
 re-created
Thread-Topic: [PATCH v2] PCI: hv: Fix hibernation in case interrupts are not
 re-created
Thread-Index: AQHWhjZu2ALom6ybqEW4kSyfVSvz+KlzZFug
Date:   Mon, 21 Sep 2020 17:01:42 +0000
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References: <20200908231759.13336-1-decui@microsoft.com>
In-Reply-To: <20200908231759.13336-1-decui@microsoft.com>
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> From: Dexuan Cui <decui@microsoft.com>
> Sent: Tuesday, September 8, 2020 4:18 PM
>=20
> Hyper-V doesn't trap and emulate the accesses to the MSI/MSI-X registers,
> and we must use hv_compose_msi_msg() to ask Hyper-V to create the IOMMU
> Interrupt Remapping Table Entries. This is not an issue for a lot of
> PCI device drivers (e.g. NVMe driver, Mellanox NIC drivers), which
> destroy and re-create the interrupts across hibernation, so
> hv_compose_msi_msg() is called automatically. However, some other PCI
> device drivers (e.g. the Nvidia driver) may not destroy and re-create
> the interrupts across hibernation, so hv_pci_resume() has to call
> hv_compose_msi_msg(), otherwise the PCI device drivers can no longer
> receive MSI/MSI-X interrupts after hibernation.
>=20
> Fixes: ac82fc832708 ("PCI: hv: Add hibernation support")
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
> Reviewed-by: Jake Oshins <jakeo@microsoft.com>
>=20
> ---
>=20
> Changes in v2:
>     Fixed a typo in the comment in hv_irq_unmask. Thanks to Michael!
>     Added Jake's Reviewed-by.
>=20
>  drivers/pci/controller/pci-hyperv.c | 44 +++++++++++++++++++++++++++++
>  1 file changed, 44 insertions(+)

Hi Lorenzo, Bjorn,
Can you please take a look at this patch?=20
I hope it still could have a chance to be in 5.9. :-)

Thanks,
-- Dexuan