diff options
Diffstat (limited to 'libre/linux-libre-pae/0002-iommu-amd-Don-t-initialise-remapping-irqdomain-if-IO.patch')
| -rw-r--r-- | libre/linux-libre-pae/0002-iommu-amd-Don-t-initialise-remapping-irqdomain-if-IO.patch | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/libre/linux-libre-pae/0002-iommu-amd-Don-t-initialise-remapping-irqdomain-if-IO.patch b/libre/linux-libre-pae/0002-iommu-amd-Don-t-initialise-remapping-irqdomain-if-IO.patch new file mode 100644 index 000000000..975223cc0 --- /dev/null +++ b/libre/linux-libre-pae/0002-iommu-amd-Don-t-initialise-remapping-irqdomain-if-IO.patch @@ -0,0 +1,71 @@ +From a4010c3d6f43dec4bf0010cab87cb3d29b4c7087 Mon Sep 17 00:00:00 2001 +From: David Woodhouse <dwmw@amazon.co.uk> +Date: Mon, 15 Mar 2021 11:15:02 +0000 +Subject: [PATCH 2/2] iommu/amd: Don't initialise remapping irqdomain if IOMMU + is disabled + +When the IOMMU is disabled, the driver still enumerates and initialises +the hardware in order to turn it off. Because IRQ remapping setup is +done early, the irqdomain is set up opportunistically. + +In commit b34f10c2dc59 ("iommu/amd: Stop irq_remapping_select() matching +when remapping is disabled") I already make the irq_remapping_select() +function check the amd_iommu_irq_setup flag because that might get +cleared only after the irqdomain setup is done, when the IVRS is parsed. + +However, in the case where 'amd_iommu=off' is passed on the command line, +the IRQ remapping setup isn't done but the amd_iommu_irq_setup flag is +still set by the early IRQ remap init code. Stop it doing that, by +bailing out of amd_iommu_prepare() early when it's disabled. + +This avoids the crash in irq_remapping_select() as it dereferences the +NULL amd_iommu_rlookup_table[]: + +[ 0.243659] Switched APIC routing to physical x2apic. +[ 0.262206] BUG: kernel NULL pointer dereference, address: 0000000000000500 +[ 0.262927] #PF: supervisor read access in kernel mode +[ 0.263390] #PF: error_code(0x0000) - not-present page +[ 0.263844] PGD 0 P4D 0 +[ 0.264135] Oops: 0000 [#1] SMP PTI +[ 0.264460] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc3 #831 +[ 0.265069] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-1.fc33 04/01/2014 +[ 0.265825] RIP: 0010:irq_remapping_select+0x57/0xb0 +[ 0.266327] Code: 4b 0c 48 3d 30 e0 a7 9e 75 0d eb 35 48 8b 00 48 3d 30 e0 a7 9e 74 2a 0f b6 50 10 39 d1 75 ed 0f b7 40 12 48 8b 15 69 e3 d2 01 <48> 8b 14 c2 48 85 d2 74 0e b8 01 00 00 00 48 3b aa 90 04 00 00 74 +[ 0.268412] RSP: 0000:ffffffff9e803db0 EFLAGS: 00010246 +[ 0.268919] RAX: 00000000000000a0 RBX: ffffffff9e803df8 RCX: 0000000000000000 +[ 0.269550] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff98120112fe79 +[ 0.270245] RBP: ffff9812011c8218 R08: 0000000000000001 R09: 000000000000000a +[ 0.270922] R10: 000000000000000a R11: f000000000000000 R12: ffff9812011c8218 +[ 0.271549] R13: ffff98120181ed88 R14: 0000000000000000 R15: 0000000000000000 +[ 0.272221] FS: 0000000000000000(0000) GS:ffff98127dc00000(0000) knlGS:0000000000000000 +[ 0.272997] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 +[ 0.273508] CR2: 0000000000000500 CR3: 0000000030810000 CR4: 00000000000006b0 +[ 0.274178] Call Trace: +[ 0.274416] irq_find_matching_fwspec+0x41/0xc0 +[ 0.274812] mp_irqdomain_create+0x65/0x150 +[ 0.275251] setup_IO_APIC+0x70/0x811 + +Fixes: a1a785b57242 ("iommu/amd: Implement select() method on remapping irqdomain") +Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=212017 +Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> +--- + drivers/iommu/amd/init.c | 3 +++ + 1 file changed, 3 insertions(+) + +diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c +index 78339b0bb8e5..398909dab640 100644 +--- a/drivers/iommu/amd/init.c ++++ b/drivers/iommu/amd/init.c +@@ -2998,6 +2998,9 @@ int __init amd_iommu_prepare(void) + { + int ret; + ++ if (amd_iommu_disabled) ++ return -ENODEV; ++ + amd_iommu_irq_remap = true; + + ret = iommu_go_to_state(IOMMU_ACPI_FINISHED); +-- +2.31.1 + |