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Commit 7e4f88da authored by Joerg Roedel's avatar Joerg Roedel Committed by Ingo Molnar
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AMD IOMMU: protect completion wait loop with iommu lock 



The unlocked polling of the ComWaitInt bit in the IOMMU completion wait
path is racy. Protect it with the iommu lock.

Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent ee2fa743

arch/x86/kernel/amd_iommu.c

+8 −4
Original line number Diff line number Diff line
@@ -101,10 +101,10 @@ static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd) 
 */

static int iommu_completion_wait(struct amd_iommu *iommu)

{

	int ret, ready = 0;

	int ret = 0, ready = 0;

	unsigned status = 0;

	struct iommu_cmd cmd;

	unsigned long i = 0;

	unsigned long flags, i = 0;



	memset(&cmd, 0, sizeof(cmd));

	cmd.data[0] = CMD_COMPL_WAIT_INT_MASK;
@@ -112,10 +112,12 @@ static int iommu_completion_wait(struct amd_iommu *iommu) 


	iommu->need_sync = 0;



	ret = iommu_queue_command(iommu, &cmd);

	spin_lock_irqsave(&iommu->lock, flags);



	ret = __iommu_queue_command(iommu, &cmd);



	if (ret)

		return ret;

		goto out;



	while (!ready && (i < EXIT_LOOP_COUNT)) {

		++i;
@@ -130,6 +132,8 @@ static int iommu_completion_wait(struct amd_iommu *iommu) 


	if (unlikely((i == EXIT_LOOP_COUNT) && printk_ratelimit()))

		printk(KERN_WARNING "AMD IOMMU: Completion wait loop failed\n");

out:

	spin_unlock_irqrestore(&iommu->lock, flags);



	return 0;

}