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iommu/amd: Fix possible irq lock inversion dependency issue 

LOCKDEP detector reported below warning:
----------------------------------------
[   23.796949] ========================================================
[   23.796950] WARNING: possible irq lock inversion dependency detected
[   23.796952] 6.8.0fix+ #811 Not tainted
[   23.796954] --------------------------------------------------------
[   23.796954] kworker/0:1/8 just changed the state of lock:
[   23.796956] ff365325e084a9b8 (&domain->lock){..-.}-{3:3}, at: amd_iommu_flush_iotlb_all+0x1f/0x50
[   23.796969] but this lock took another, SOFTIRQ-unsafe lock in the past:
[   23.796970]  (pd_bitmap_lock){+.+.}-{3:3}
[   23.796972]

               and interrupts could create inverse lock ordering between them.

[   23.796973]
               other info that might help us debug this:
[   23.796974] Chain exists of:
                 &domain->lock --> &dev_data->lock --> pd_bitmap_lock

[   23.796980]  Possible interrupt unsafe locking scenario:

[   23.796981]        CPU0                    CPU1
[   23.796982]        ----                    ----
[   23.796983]   lock(pd_bitmap_lock);
[   23.796985]                                local_irq_disable();
[   23.796985]                                lock(&domain->lock);
[   23.796988]                                lock(&dev_data->lock);
[   23.796990]   <Interrupt>
[   23.796991]     lock(&domain->lock);

Fix this issue by disabling interrupt when acquiring pd_bitmap_lock.

Note that this is temporary fix. We have a plan to replace custom bitmap
allocator with IDA allocator.

Fixes: 87a6f1f22c ("iommu/amd: Introduce per-device domain ID to fix potential TLB aliasing issue")
Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Link: https://lore.kernel.org/r/20240404102717.6705-1-vasant.hegde@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Vasant Hegde 2024-04-04 10:27:17 +00:00 committed by Joerg Roedel
parent fec50db703
commit 84b1cec4fa
1 changed files with 7 additions and 4 deletions
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11
drivers/iommu/amd/iommu.c
View File

@ -1692,26 +1692,29 @@ int amd_iommu_complete_ppr(struct pci_dev *pdev, u32 pasid,
static u16 domain_id_alloc(void)
{
unsigned long flags;
int id;
spin_lock(&pd_bitmap_lock);
spin_lock_irqsave(&pd_bitmap_lock, flags);
id = find_first_zero_bit(amd_iommu_pd_alloc_bitmap, MAX_DOMAIN_ID);
BUG_ON(id == 0);
if (id > 0 && id < MAX_DOMAIN_ID)
__set_bit(id, amd_iommu_pd_alloc_bitmap);
else
id = 0;
spin_unlock(&pd_bitmap_lock);
spin_unlock_irqrestore(&pd_bitmap_lock, flags);
return id;
}
static void domain_id_free(int id)
{
spin_lock(&pd_bitmap_lock);
unsigned long flags;
spin_lock_irqsave(&pd_bitmap_lock, flags);
if (id > 0 && id < MAX_DOMAIN_ID)
__clear_bit(id, amd_iommu_pd_alloc_bitmap);
spin_unlock(&pd_bitmap_lock);
spin_unlock_irqrestore(&pd_bitmap_lock, flags);
}
static void free_gcr3_tbl_level1(u64 *tbl)