Re: git: 65b133e5d292 - main - x86: allow to have more than one kind of IOMMU

On Wed, Sep 04, 2024 at 06:06:00PM -0700, Cy Schubert wrote:
> ??() at 0/frame 0xffffffff81f058e0
> acpi_pci_get_dma_tag() at acpi_pci_get_dma_tag+0x34/frame 0xffffffff81f05900

One more method is needed.  Updated patch is below.

commit 99e3d96fc1a2b1d5cac5a635608ec3044ec4fa13
Author: Konstantin Belousov <kib@FreeBSD.org>
Date:   Thu Sep 5 03:33:34 2024 +0300

    x86: always provide dummy x86_iommu virtual methods
    
    to make configurations where vendor-specific IOMMU not yet implemented
    but IOMMU is enabled in config, work when calling into MSI/IOAPIC
    interrupt remapping.
    
    Reported by:    cy
    Sponsored by:   Advanced Micro Devices (AMD)
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week

diff --git a/sys/x86/iommu/iommu_utils.c b/sys/x86/iommu/iommu_utils.c
index 2c647fd21c67..2011c632f770 100644
--- a/sys/x86/iommu/iommu_utils.c
+++ b/sys/x86/iommu/iommu_utils.c
@@ -190,12 +190,60 @@ SYSCTL_INT(_hw_iommu, OID_AUTO, batch_coalesce, CTLFLAG_RWTUN,
     &iommu_qi_batch_coalesce, 0,
     "Number of qi batches between interrupt");
 
-static struct x86_iommu *x86_iommu;
+static struct iommu_unit *
+x86_no_iommu_find(device_t dev, bool verbose)
+{
+	return (NULL);
+}
+
+static int
+x86_no_iommu_alloc_msi_intr(device_t src, u_int *cookies, u_int count)
+{
+	return (EOPNOTSUPP);
+}
+
+static int
+x86_no_iommu_map_msi_intr(device_t src, u_int cpu, u_int vector,
+    u_int cookie, uint64_t *addr, uint32_t *data)
+{
+	return (EOPNOTSUPP);
+}
+
+static int
+x86_no_iommu_unmap_msi_intr(device_t src, u_int cookie)
+{
+	return (0);
+}
+
+static int
+x86_no_iommu_map_ioapic_intr(u_int ioapic_id, u_int cpu, u_int vector,
+    bool edge, bool activehi, int irq, u_int *cookie, uint32_t *hi,
+    uint32_t *lo)
+{
+	return (EOPNOTSUPP);
+}
+
+static int
+x86_no_iommu_unmap_ioapic_intr(u_int ioapic_id, u_int *cookie)
+{
+	return (0);
+}
+
+static struct x86_iommu x86_no_iommu = {
+	.find = x86_no_iommu_find,
+	.alloc_msi_intr = x86_no_iommu_alloc_msi_intr,
+	.map_msi_intr = x86_no_iommu_map_msi_intr,
+	.unmap_msi_intr = x86_no_iommu_unmap_msi_intr,
+	.map_ioapic_intr = x86_no_iommu_map_ioapic_intr,
+	.unmap_ioapic_intr = x86_no_iommu_unmap_ioapic_intr,
+};
+
+static struct x86_iommu *x86_iommu = &x86_no_iommu;
 
 void
 set_x86_iommu(struct x86_iommu *x)
 {
-	MPASS(x86_iommu == NULL);
+	MPASS(x86_iommu == &x86_no_iommu);
 	x86_iommu = x;
 }