From: David Woodhouse <dwmw@amazon.co.uk>
Date: Sat, 24 Oct 2020 21:35:33 +0000 (+0100)
Subject: iommu/hyper-v: Disable IRQ pseudo-remapping if 15 bit APIC IDs are available
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=e8c460112f20a2dd0ab9f916b86da9e5fb0c42dd;p=users%2Fdwmw2%2Flinux.git

iommu/hyper-v: Disable IRQ pseudo-remapping if 15 bit APIC IDs are available

If the 15-bit APIC ID support is present in emulated MSI then there's no
need for the pseudo-remapping support.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201024213535.443185-34-dwmw2@infradead.org

(cherry picked from commit bf27ef8a77d8da38c9f35f8f6aab013a2dcf175f)
---

diff --git a/drivers/iommu/hyperv-iommu.c b/drivers/iommu/hyperv-iommu.c
index 8919c1c70b68a..164fe3c786a49 100644
--- a/drivers/iommu/hyperv-iommu.c
+++ b/drivers/iommu/hyperv-iommu.c
@@ -143,6 +143,7 @@ static int __init hyperv_prepare_irq_remapping(void)
 	int i;
 
 	if (!hypervisor_is_type(X86_HYPER_MS_HYPERV) ||
+	    x86_init.hyper.msi_ext_dest_id() ||
 	    !x2apic_supported())
 		return -ENODEV;