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From:   kan.liang@linux.intel.com
To:     joro@8bytes.org, will@kernel.org, baolu.lu@linux.intel.com,
        dwmw2@infradead.org, robin.murphy@arm.com, robert.moore@intel.com,
        rafael.j.wysocki@intel.com, lenb@kernel.org, iommu@lists.linux.dev,
        linux-kernel@vger.kernel.org
Cc:     Kan Liang <kan.liang@linux.intel.com>
Subject: [PATCH 1/7] iommu/vt-d: Support size of the register set in DRHD
Date:   Wed, 11 Jan 2023 12:24:58 -0800
Message-Id: <20230111202504.378258-2-kan.liang@linux.intel.com>
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From: Kan Liang <kan.liang@linux.intel.com>

A new field, which indicates the size of the remapping hardware register
set for this remapping unit, is introduced in the DMA-remapping hardware
unit definition (DRHD) structure with the VT-d Spec 4.0.
With the information, SW doesn't need to 'guess' the size of the
register set anymore.

Update the struct acpi_dmar_hardware_unit to reflect the field.

Store the size of the register set in struct dmar_drhd_unit for each
dmar device.

The 'size' information is ResvZ for the old BIOS and platforms. Fall
back to the old guessing method. There is nothing changed.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
---
 drivers/iommu/intel/dmar.c | 25 ++++++++++++++++++-------
 include/acpi/actbl1.h      |  2 +-
 include/linux/dmar.h       |  1 +
 3 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index b00a0ceb2d13..6a411d964474 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -399,6 +399,13 @@ dmar_find_dmaru(struct acpi_dmar_hardware_unit *drhd)
 	return NULL;
 }
 
+/* The size of the register set is 2 ^ N 4 KB pages. */
+static unsigned long
+dmar_get_drhd_reg_size(u8 npages)
+{
+	return 1UL << (npages + 12);
+}
+
 /*
  * dmar_parse_one_drhd - parses exactly one DMA remapping hardware definition
  * structure which uniquely represent one DMA remapping hardware unit
@@ -427,6 +434,7 @@ static int dmar_parse_one_drhd(struct acpi_dmar_header *header, void *arg)
 	memcpy(dmaru->hdr, header, header->length);
 	dmaru->reg_base_addr = drhd->address;
 	dmaru->segment = drhd->segment;
+	dmaru->reg_size = dmar_get_drhd_reg_size(drhd->size);
 	dmaru->include_all = drhd->flags & 0x1; /* BIT0: INCLUDE_ALL */
 	dmaru->devices = dmar_alloc_dev_scope((void *)(drhd + 1),
 					      ((void *)drhd) + drhd->header.length,
@@ -880,6 +888,7 @@ dmar_validate_one_drhd(struct acpi_dmar_header *entry, void *arg)
 	struct acpi_dmar_hardware_unit *drhd;
 	void __iomem *addr;
 	u64 cap, ecap;
+	unsigned long size;
 
 	drhd = (void *)entry;
 	if (!drhd->address) {
@@ -887,10 +896,11 @@ dmar_validate_one_drhd(struct acpi_dmar_header *entry, void *arg)
 		return -EINVAL;
 	}
 
+	size = dmar_get_drhd_reg_size(drhd->size);
 	if (arg)
-		addr = ioremap(drhd->address, VTD_PAGE_SIZE);
+		addr = ioremap(drhd->address, size);
 	else
-		addr = early_ioremap(drhd->address, VTD_PAGE_SIZE);
+		addr = early_ioremap(drhd->address, size);
 	if (!addr) {
 		pr_warn("Can't validate DRHD address: %llx\n", drhd->address);
 		return -EINVAL;
@@ -902,7 +912,7 @@ dmar_validate_one_drhd(struct acpi_dmar_header *entry, void *arg)
 	if (arg)
 		iounmap(addr);
 	else
-		early_iounmap(addr, VTD_PAGE_SIZE);
+		early_iounmap(addr, size);
 
 	if (cap == (uint64_t)-1 && ecap == (uint64_t)-1) {
 		warn_invalid_dmar(drhd->address, " returns all ones");
@@ -956,17 +966,18 @@ static void unmap_iommu(struct intel_iommu *iommu)
 /**
  * map_iommu: map the iommu's registers
  * @iommu: the iommu to map
- * @phys_addr: the physical address of the base resgister
+ * @drhd: DMA remapping hardware definition structure
  *
  * Memory map the iommu's registers.  Start w/ a single page, and
  * possibly expand if that turns out to be insufficent.
  */
-static int map_iommu(struct intel_iommu *iommu, u64 phys_addr)
+static int map_iommu(struct intel_iommu *iommu, struct dmar_drhd_unit *drhd)
 {
+	u64 phys_addr = drhd->reg_base_addr;
 	int map_size, err=0;
 
 	iommu->reg_phys = phys_addr;
-	iommu->reg_size = VTD_PAGE_SIZE;
+	iommu->reg_size = drhd->reg_size;
 
 	if (!request_mem_region(iommu->reg_phys, iommu->reg_size, iommu->name)) {
 		pr_err("Can't reserve memory\n");
@@ -1050,7 +1061,7 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)
 	}
 	sprintf(iommu->name, "dmar%d", iommu->seq_id);
 
-	err = map_iommu(iommu, drhd->reg_base_addr);
+	err = map_iommu(iommu, drhd);
 	if (err) {
 		pr_err("Failed to map %s\n", iommu->name);
 		goto error_free_seq_id;
diff --git a/include/acpi/actbl1.h b/include/acpi/actbl1.h
index 4175dce3967c..bdded0ac46eb 100644
--- a/include/acpi/actbl1.h
+++ b/include/acpi/actbl1.h
@@ -802,7 +802,7 @@ struct acpi_dmar_pci_path {
 struct acpi_dmar_hardware_unit {
 	struct acpi_dmar_header header;
 	u8 flags;
-	u8 reserved;
+	u8 size;		/* Size of the register set */
 	u16 segment;
 	u64 address;		/* Register Base Address */
 };
diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index d81a51978d01..51d498f0a02b 100644
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -46,6 +46,7 @@ struct dmar_drhd_unit {
 	u8	include_all:1;
 	u8	gfx_dedicated:1;	/* graphic dedicated	*/
 	struct intel_iommu *iommu;
+	unsigned long reg_size;		/* size of register set */
 };
 
 struct dmar_pci_path {
-- 
2.35.1