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From: Sairaj Kodilkar <sarunkod@amd.com>
To: <qemu-devel@nongnu.org>
Cc: <mst@redhat.com>, <marcel.apfelbaum@gmail.com>,
	<pbonzini@redhat.com>, <richard.henderson@linaro.org>,
	<eduardo@habkost.net>, <suravee.suthikulpanit@amd.com>,
	<alejandro.j.jimenez@oracle.com>, <joao.m.martins@oracle.com>,
	<sarunkod@amd.com>
Subject: [PATCH v3 0/2] amd_iommu: Fixes
Date: Fri, 16 May 2025 15:35:33 +0530	[thread overview]
Message-ID: <20250516100535.4980-1-sarunkod@amd.com> (raw)

Fix following two issues in the amd viommu
1. The guest fails to setup the passthrough device when for following setup
   because amd iommu enables the no DMA memory region even when guest is 
   using DMA remapping mode.

    -device amd-iommu,intremap=on,xtsup=on,pt=on \
    -device vfio-pci,host=<DEVID> \

    and guest forcing DMA remap mode e.g. 'iommu.passthrough=0'

    which will cause failures from QEMU:

    qemu-system-x86_64: AHCI: Failed to start DMA engine: bad command list buffer address
    qemu-system-x86_64: AHCI: Failed to start FIS receive engine: bad FIS receive buffer address
    qemu-system-x86_64: AHCI: Failed to start DMA engine: bad command list buffer address
    qemu-system-x86_64: AHCI: Failed to start FIS receive engine: bad FIS receive buffer address
    qemu-system-x86_64: AHCI: Failed to start DMA engine: bad command list buffer address


2. The guest fails to boot with xtsup=on and <= 255 vCPUs, because amd_iommu
   does not enable x2apic mode.

base commit 56c6e249b6988c1b6edc2dd34ebb0f1e570a1365 (v10.0.0-rc3)

Sairaj Kodilkar (1):
  hw/i386/amd_iommu: Fix device setup failure when PT is on.

Vasant Hegde (1):
  hw/i386/amd_iommu: Fix xtsup when vcpus < 255

 hw/i386/amd_iommu.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

-- 
2.34.1



             reply	other threads:[~2025-05-16 10:07 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-16 10:05 Sairaj Kodilkar [this message]
2025-05-16 10:05 ` [PATCH v3 1/2] hw/i386/amd_iommu: Fix device setup failure when PT is on Sairaj Kodilkar
2025-05-16 14:43   ` Philippe Mathieu-Daudé
2025-05-19  3:59     ` Sairaj Kodilkar
2025-05-16 10:05 ` [PATCH v3 2/2] hw/i386/amd_iommu: Fix xtsup when vcpus < 255 Sairaj Kodilkar
2025-05-16 14:38   ` Philippe Mathieu-Daudé
2025-05-19  7:35     ` Vasant Hegde
2025-05-16 10:36 ` [PATCH v3 0/2] amd_iommu: Fixes Michael S. Tsirkin
2025-05-16 10:45   ` Sairaj Kodilkar
2025-06-02 20:54 ` Michael Tokarev
2025-06-10  8:33   ` Sairaj Kodilkar

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