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| author | Nuno Das Neves <nunodasneves@linux.microsoft.com> | 2022-11-17 23:11:39 +0300 |
|---|---|---|
| committer | Wei Liu <wei.liu@kernel.org> | 2022-11-28 19:48:20 +0300 |
| commit | fea858dc5d901626e5d794037b5bff9f59b9ded7 (patch) | |
| tree | f207353c16bcb7322a2edc098df715fb3595ee5f /arch/x86/kernel/cpu/mshyperv.c | |
| parent | 0408f16b43e578e70ad12a857159a0a771cfaa7c (diff) | |
| download | linux-fea858dc5d901626e5d794037b5bff9f59b9ded7.tar.xz | |
iommu/hyper-v: Allow hyperv irq remapping without x2apic
If x2apic is not available, hyperv-iommu skips remapping
irqs. This breaks root partition which always needs irqs
remapped.
Fix this by allowing irq remapping regardless of x2apic,
and change hyperv_enable_irq_remapping() to return
IRQ_REMAP_XAPIC_MODE in case x2apic is missing.
Tested with root and non-root hyperv partitions.
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: Tianyu Lan <Tianyu.Lan@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1668715899-8971-1-git-send-email-nunodasneves@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Diffstat (limited to 'arch/x86/kernel/cpu/mshyperv.c')
| -rw-r--r-- | arch/x86/kernel/cpu/mshyperv.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index 831613959a92..46668e255421 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -475,6 +475,12 @@ static bool __init ms_hyperv_x2apic_available(void) * (logically) generates MSIs directly to the system APIC irq domain. * There is no HPET, and PCI MSI/MSI-X interrupts are remapped by the * pci-hyperv host bridge. + * + * Note: for a Hyper-V root partition, this will always return false. + * The hypervisor doesn't expose these HYPERV_CPUID_VIRT_STACK_* cpuids by + * default, they are implemented as intercepts by the Windows Hyper-V stack. + * Even a nested root partition (L2 root) will not get them because the + * nested (L1) hypervisor filters them out. */ static bool __init ms_hyperv_msi_ext_dest_id(void) { |