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intel-iommu-PMEN support

PATCH In review mark gross 3 participants 4 messages Nov 16, 2007 – Nov 20, 2007 PCI

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mark gross

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#0 lore raw

PATCH 1/1 intel-iommu-PMEN support

The following patch adds support for protected memory enable bits by clearing them if they are set at startup time. Some future boot loaders or firmware could have this bit set after it loads the kernel, and it needs to be cleared if DMA's are going to happen effectively.

please apply

--mgross

drivers/pci/intel-iommu.c +20 -1
Index: linux-2.6.23-rc2-iommu/drivers/pci/intel-iommu.c
===================================================================
@@ -692,6 +692,23 @@
 		DMA_TLB_PSI_FLUSH, non_present_entry_flush);
 }
 
+static void iommu_disable_protect_mem_regions(struct intel_iommu *iommu)
+{
+	u32 pmen;
+	unsigned long flags;
+
+	spin_lock_irqsave(&iommu->register_lock, flags);
+	pmen = readl(iommu->reg + DMAR_PMEN_REG);
+	pmen &= ~DMA_PMEN_EPM;
+	writel(pmen, iommu->reg + DMAR_PMEN_REG);
+
+	/* wait for the protected region status bit to clear */
+	IOMMU_WAIT_OP(iommu, DMAR_PMEN_REG,
+		readl, (pmen & DMA_PMEN_PRS), pmen);
+
+	spin_unlock_irqrestore(&iommu->register_lock, flags);
+}
+
 static int iommu_enable_translation(struct intel_iommu *iommu)
 {
 	u32 sts;
@@ -745,7 +762,7 @@
 	"non-zero reserved fields in PTE",
 	"Unknown"
 };
-#define MAX_FAULT_REASON_IDX 	ARRAY_SIZE(fault_reason_strings) - 1
+#define MAX_FAULT_REASON_IDX 	(ARRAY_SIZE(fault_reason_strings) - 1)
 
 char *dmar_get_fault_reason(u8 fault_reason)
 {
@@ -1730,6 +1747,8 @@
 		iommu_flush_context_global(iommu, 0);
 		iommu_flush_iotlb_global(iommu, 0);
 
+		iommu_disable_protect_mem_regions(iommu);
+
 		ret = iommu_enable_translation(iommu);
 		if (ret)
 			goto error;
drivers/pci/intel-iommu.h +5 -1
Index: linux-2.6.23-rc2-iommu/drivers/pci/intel-iommu.h
===================================================================
@@ -71,7 +71,7 @@
 		hi = readl(dmar + reg + 4); \
 		(((u64) hi) << 32) + lo; })
 */
-static inline u64 dmar_readq(void *addr)
+static inline u64 dmar_readq(void __iomem *addr)
 {
 	u32 lo, hi;
 	lo = readl(addr);
@@ -139,6 +139,10 @@
 #define DMA_TLB_IH_NONLEAF (((u64)1) << 6)
 #define DMA_TLB_MAX_SIZE (0x3f)
 
+/* PMEN_REG */
+#define DMA_PMEN_EPM (((u32)1)<<31)
+#define DMA_PMEN_PRS (((u32)1)<<0)
+
 /* GCMD_REG */
 #define DMA_GCMD_TE (((u32)1) << 31)
 #define DMA_GCMD_SRTP (((u32)1) << 30)
Acked-by on v1 1/1
#1 lore raw
Quoted 11 lines · mark gross

The following patch adds support for protected memory enable bits by clearing them if they are set at startup time. Some future boot loaders or firmware could have this bit set after it loads the kernel, and it needs to be cleared if DMA's are going to happen effectively.

please apply

--mgross

Mark, please try in the future to not mix unrelated changes such as these. This patch should've been two patches, one to disable protected memory enable and the other to do the cleanups.

drivers/pci/intel-iommu.c

Quoted 5 lines
drivers/pci/intel-iommu.c +2 -2
-#define MAX_FAULT_REASON_IDX 	ARRAY_SIZE(fault_reason_strings) - 1
+#define MAX_FAULT_REASON_IDX 	(ARRAY_SIZE(fault_reason_strings) - 1)
 
-static inline u64 dmar_readq(void *addr)
+static inline u64 dmar_readq(void __iomem *addr)

Cheers,
Muli

#2 lore raw
In reply to mark gross

drivers/pci/intel-iommu.c line 765

Quoted 2 lines · On Fri, 16 Nov 2007 14:39:57 -0800 mark gross <[email protected]> wrote:
drivers/pci/intel-iommu.c +1 -1
-#define MAX_FAULT_REASON_IDX 	ARRAY_SIZE(fault_reason_strings) - 1
+#define MAX_FAULT_REASON_IDX 	(ARRAY_SIZE(fault_reason_strings) - 1)

hm. The logic in there looks screwy.

static char *fault_reason_strings[] =
{
"Software",
"Present bit in root entry is clear",
"Present bit in context entry is clear",
"Invalid context entry",
"Access beyond MGAW",
"PTE Write access is not set",
"PTE Read access is not set",
"Next page table ptr is invalid",
"Root table address invalid",
"Context table ptr is invalid",
"non-zero reserved fields in RTP",
"non-zero reserved fields in CTP",
"non-zero reserved fields in PTE",
"Unknown"
};
#define MAX_FAULT_REASON_IDX (ARRAY_SIZE(fault_reason_strings) - 1)

char *dmar_get_fault_reason(u8 fault_reason)

{
	if (fault_reason >= MAX_FAULT_REASON_IDX)
		return fault_reason_strings[MAX_FAULT_REASON_IDX - 1];
	else
		return fault_reason_strings[fault_reason];
}

so all invalid fault_reasons will cause us to display "non-zero reserved fields in PTE".

Why not just do

	if (fault_reason >= ARRAY_SIZE(fault_reason_strings))
		return "Unknown";
	return fault_reason_strings[fault_reason];

?

(might as well make fault_reason_strings[] const, too).

author
#3 lore raw
Quoted 7 lines · Andrew Morton

drivers/pci/intel-iommu.c line 765

Quoted 2 lines · On Fri, 16 Nov 2007 14:39:57 -0800 mark gross <[email protected]> wrote:
drivers/pci/intel-iommu.c +1 -1
-#define MAX_FAULT_REASON_IDX 	ARRAY_SIZE(fault_reason_strings) - 1
+#define MAX_FAULT_REASON_IDX 	(ARRAY_SIZE(fault_reason_strings) - 1)

hm. The logic in there looks screwy.

I didn't like it when they added the -1 to the above, but after looking at it sideways for a while I convinced myself that it was ok. so I thought it be good to add the parentheses.

Quoted 30 lines

static char *fault_reason_strings[] =
{
"Software",
"Present bit in root entry is clear",
"Present bit in context entry is clear",
"Invalid context entry",
"Access beyond MGAW",
"PTE Write access is not set",
"PTE Read access is not set",
"Next page table ptr is invalid",
"Root table address invalid",
"Context table ptr is invalid",
"non-zero reserved fields in RTP",
"non-zero reserved fields in CTP",
"non-zero reserved fields in PTE",
"Unknown"
};
#define MAX_FAULT_REASON_IDX (ARRAY_SIZE(fault_reason_strings) - 1)

char *dmar_get_fault_reason(u8 fault_reason)

{
	if (fault_reason >= MAX_FAULT_REASON_IDX)
		return fault_reason_strings[MAX_FAULT_REASON_IDX - 1];
	else
		return fault_reason_strings[fault_reason];
}
Quoted 2 lines

so all invalid fault_reasons will cause us to display "non-zero reserved fields in PTE".

GAH! Thats wrong.

I also don't like the use of >= here, its harder for me to parse in my head than just >.

Quoted 8 lines

Why not just do

	if (fault_reason >= ARRAY_SIZE(fault_reason_strings))
		return "Unknown";
	return fault_reason_strings[fault_reason];

?

Why not indeed. :)

Quoted 2 lines

(might as well make fault_reason_strings[] const, too).

Thats a good thing too.

I'll put together a patch this morning to address these think-ohs.

--mgross