Re: [PATCH 1/2 V3] perf/x86/amd: Adding IOMMU PC resource management
From: Suravee Suthikulanit
Date: Tue May 28 2013 - 12:29:32 EST
Joerg,
Thanks for the review. I'll post new patch set to address your comment
shortly.
Suravee
On 5/28/2013 6:07 AM, Joerg Roedel wrote:
On Fri, May 17, 2013 at 02:43:31PM -0500, Suthikulpanit, Suravee wrote:
From: Steven L Kinney <Steven.Kinney@xxxxxxx>
Add functionality to check the availability of the AMD IOMMU Performance
Counters and export this functionality to other core drivers, such as in this
case, a perf AMD IOMMU PMU. This feature is not bound to any specific AMD
family/model other than the presence of the IOMMU with PC enabled.
The AMD IOMMU PC support static counting only at this time.
Signed-off-by: Steven Kinney <steven.kinney@xxxxxxx>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
---
V2 Changes:
- Modify the amd_iommu_pc_get_set_reg_val function
to support 64 bit values.
- Fix logic to properly clear amd_iommu_pc_present when
initialization failed.
drivers/iommu/amd_iommu_init.c | 121 ++++++++++++++++++++++++++++++++++++++-
drivers/iommu/amd_iommu_proto.h | 7 +++
drivers/iommu/amd_iommu_types.h | 12 +++-
3 files changed, 134 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index bf51abb..395fa29 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -154,6 +154,7 @@ bool amd_iommu_iotlb_sup __read_mostly = true;
u32 amd_iommu_max_pasids __read_mostly = ~0;
bool amd_iommu_v2_present __read_mostly;
+bool amd_iommu_pc_present __read_mostly;
bool amd_iommu_force_isolation __read_mostly;
@@ -371,21 +372,21 @@ static void iommu_disable(struct amd_iommu *iommu)
*/
static u8 __iomem * __init iommu_map_mmio_space(u64 address)
{
- if (!request_mem_region(address, MMIO_REGION_LENGTH, "amd_iommu")) {
+ if (!request_mem_region(address, MMIO_REG_END_OFFSET, "amd_iommu")) {
This length needs to be different on IOMMUv1 systems where the MMI
region is only 16kb large. Only use MMIO_REG_END_OFFSET on IOMMUv2
systems.
+static void init_iommu_perf_ctr(struct amd_iommu *iommu)
+{
+ u64 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");
+ amd_iommu_pc_present = false;
+ return;
+ }
+
+ pr_info("AMD-Vi: IOMMU performance counters " "supported\n");
Why are this two strings? This makes it hard to grep for the message.
+u8 amd_iommu_pc_get_max_banks(u16 devid)
+{
+ struct amd_iommu *iommu;
+
+ /* locate the iommu governing the devid */
+ iommu = amd_iommu_rlookup_table[devid];
+
+ if (iommu)
+ return iommu->max_banks;
+
+ return -ENODEV;
+}
+EXPORT_SYMBOL(amd_iommu_pc_get_max_banks);
You can't return -ENODEV in a function returning u8. Return int instead.
+
+bool amd_iommu_pc_supported(void)
+{
+ return amd_iommu_pc_present;
+}
+EXPORT_SYMBOL(amd_iommu_pc_supported);
+
+u8 amd_iommu_pc_get_max_counters(u16 devid)
+{
+ struct amd_iommu *iommu;
+
+ /* locate the iommu governing the devid */
+ iommu = amd_iommu_rlookup_table[devid];
+
+ if (iommu)
+ return iommu->max_counters;
+
+ return -ENODEV;
+}
+EXPORT_SYMBOL(amd_iommu_pc_get_max_counters);
Same here. Please don't return negative values as u8.
+
+int amd_iommu_pc_get_set_reg_val(u16 devid, u8 bank, u8 cntr, u8 fxn,
+ u64 *value, bool is_write)
+{
+ struct amd_iommu *iommu;
+ u32 offset;
+ u32 max_offset_lim;
+
+ /* Make sure the IOMMU PC resource is available */
+ if (!amd_iommu_pc_present) {
+ pr_info("AMD IOMMU - PC Not supported.\n");
This message is redundant. You already print about about performance
counter availability in the init code. Please remove it.
+ return -ENODEV;
+ }
+
+ /* locate the iommu associated with the device ID */
+ iommu = amd_iommu_rlookup_table[devid];
+ if (iommu == NULL)
+ return -ENODEV;
+
+ /* check for valid iommu pc register indexing */
+ if (fxn < 0 || fxn > 0x28 || (fxn & 7))
+ return -ENODEV;
Does this check for calling errors? If so, you might consider turning
this into a WARN_ON.
+
+ offset = (u32)(((0x40|bank) << 12) | (cntr << 8) | fxn);
+
+ /* limit the offset to the hw defined mmio region aperture */
+ max_offset_lim = (u32)(((0x40|iommu->max_banks) << 12) |
+ (iommu->max_counters << 8) | 0x28);
+ if ((offset < MMIO_CNTR_REG_OFFSET) ||
+ (offset > max_offset_lim))
+ return -EINVAL;
+
+ if (is_write) {
+ writel((u32)*value, iommu->mmio_base + offset);
+ writel((*value >> 32), iommu->mmio_base + offset + 4);
+ } else {
+ *value = readl(iommu->mmio_base + offset + 4);
+ *value <<= 32;
+ *value = readl(iommu->mmio_base + offset);
+ }
+
+ return 0;
+}
Joerg
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