iommu/vt-d: Put IRTE back into posted MSI mode if vCPU posting is disabled

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commit 2454823e97 upstream.

Add a helper to take care of reconfiguring an IRTE to deliver IRQs to the
host, i.e. not to a vCPU, and use the helper when an IRTE's vCPU affinity
is nullified, i.e. when KVM puts an IRTE back into "host" mode.  Because
posted MSIs use an ephemeral IRTE, using modify_irte() puts the IRTE into
full remapped mode, i.e. unintentionally disables posted MSIs on the IRQ.

Fixes: ed1e48ea43 ("iommu/vt-d: Enable posted mode for device MSIs")
Cc: stable@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20250315025135.2365846-2-seanjc@google.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Sean Christopherson 2025-03-19 10:20:59 +08:00 • committed by Greg Kroah-Hartman

parent e5dd974d6e

commit c95a438d2c

1 changed files with 13 additions and 6 deletions

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drivers/iommu/intel/irq_remapping.c

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