Re: [PATCH 1/2] IOMMU/AMD: Adding IOMMU PC resource management

From: Suravee Suthikulanit
Date: Tue May 14 2013 - 10:37:35 EST


On 5/14/2013 2:09 AM, Peter Zijlstra wrote:
On Mon, May 13, 2013 at 04:43:44PM -0500, steven.kinney@xxxxxxx wrote:
+static void init_iommu_perf_ctr(struct amd_iommu *iommu)
+{
+ u32 val = 0xabcd, val2 = 0;
+
+ if (!iommu_feature(iommu, FEATURE_PC))
+ return;
+
+ amd_iommu_pc_present = true;
+
+ /* Check if the performance counters can be written to */
+ if ((0 != amd_iommu_pc_get_set_reg_val(0, 0, 0, 0, &val, true)) ||
+ (0 != amd_iommu_pc_get_set_reg_val(0, 0, 0, 0, &val2, false)) ||
+ (val != val2)) {
+ pr_err("AMD-Vi: Unable to write to IOMMU perf counter.\n");
Would it make sense to clear amd_iommu_pc_present here?
Yes, I'll take care of this here.

Thank you,

Surave

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