From: Joerg Roedel <joerg.roedel@amd.com>
Date: Thu, 3 Sep 2009 13:08:09 +0000 (+0200)
Subject: x86/amd-iommu: Panic if IOMMU command buffer reset fails
X-Git-Tag: v2.6.32-rc1~727^2^2~2^3~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b26e81b871bd18184968f0bb3f12945906eadfce;p=profile%2Fivi%2Fkernel-x86-ivi.git

x86/amd-iommu: Panic if IOMMU command buffer reset fails

To prevent the driver from doing recursive command buffer
resets, just panic when that recursion happens.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---

diff --git a/arch/x86/include/asm/amd_iommu_types.h b/arch/x86/include/asm/amd_iommu_types.h
index c54bc979..e676746 100644
--- a/arch/x86/include/asm/amd_iommu_types.h
+++ b/arch/x86/include/asm/amd_iommu_types.h
@@ -337,6 +337,9 @@ struct amd_iommu {
 	/* if one, we need to send a completion wait command */
 	bool need_sync;
 
+	/* becomes true if a command buffer reset is running */
+	bool reset_in_progress;
+
 	/* default dma_ops domain for that IOMMU */
 	struct dma_ops_domain *default_dom;
 };
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 2333d61..b62a2f6 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -553,9 +553,16 @@ static void reset_iommu_command_buffer(struct amd_iommu *iommu)
 {
 	pr_err("AMD-Vi: Resetting IOMMU command buffer\n");
 
+	if (iommu->reset_in_progress)
+		panic("AMD-Vi: ILLEGAL_COMMAND_ERROR while resetting command buffer\n");
+
+	iommu->reset_in_progress = true;
+
 	amd_iommu_reset_cmd_buffer(iommu);
 	flush_all_devices_for_iommu(iommu);
 	flush_all_domains_on_iommu(iommu);
+
+	iommu->reset_in_progress = false;
 }
 
 /****************************************************************************