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Subject[PATCH v2 7/7] iommu/vt-d: Remove lazy allocation of domains
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The generic IOMMU code will allocate and attach a default domain to each
device that comes online. This patch removes the lazy domain allocation
and early reserved region mapping that is now redundant.

Signed-off-by: James Sewart <jamessewart@arista.com>
---
drivers/iommu/intel-iommu.c | 300 +-----------------------------------
1 file changed, 5 insertions(+), 295 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 2c9d793af394..f8c0c3e16935 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2605,118 +2605,6 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
return domain;
}

-static int get_last_alias(struct pci_dev *pdev, u16 alias, void *opaque)
-{
- *(u16 *)opaque = alias;
- return 0;
-}
-
-static struct dmar_domain *find_or_alloc_domain(struct device *dev, int gaw)
-{
- struct device_domain_info *info = NULL;
- struct dmar_domain *domain = NULL;
- struct intel_iommu *iommu;
- u16 dma_alias;
- unsigned long flags;
- u8 bus, devfn;
-
- iommu = device_to_iommu(dev, &bus, &devfn);
- if (!iommu)
- return NULL;
-
- if (dev_is_pci(dev)) {
- struct pci_dev *pdev = to_pci_dev(dev);
-
- pci_for_each_dma_alias(pdev, get_last_alias, &dma_alias);
-
- spin_lock_irqsave(&device_domain_lock, flags);
- info = dmar_search_domain_by_dev_info(pci_domain_nr(pdev->bus),
- PCI_BUS_NUM(dma_alias),
- dma_alias & 0xff);
- if (info) {
- iommu = info->iommu;
- domain = info->domain;
- }
- spin_unlock_irqrestore(&device_domain_lock, flags);
-
- /* DMA alias already has a domain, use it */
- if (info)
- goto out;
- }
-
- /* Allocate and initialize new domain for the device */
- domain = alloc_domain(0);
- if (!domain)
- return NULL;
- if (domain_init(domain, iommu, gaw)) {
- domain_exit(domain);
- return NULL;
- }
-
-out:
-
- return domain;
-}
-
-static struct dmar_domain *set_domain_for_dev(struct device *dev,
- struct dmar_domain *domain)
-{
- struct intel_iommu *iommu;
- struct dmar_domain *tmp;
- u16 req_id, dma_alias;
- u8 bus, devfn;
-
- iommu = device_to_iommu(dev, &bus, &devfn);
- if (!iommu)
- return NULL;
-
- req_id = ((u16)bus << 8) | devfn;
-
- if (dev_is_pci(dev)) {
- struct pci_dev *pdev = to_pci_dev(dev);
-
- pci_for_each_dma_alias(pdev, get_last_alias, &dma_alias);
-
- /* register PCI DMA alias device */
- if (req_id != dma_alias) {
- tmp = dmar_insert_one_dev_info(iommu, PCI_BUS_NUM(dma_alias),
- dma_alias & 0xff, NULL, domain);
-
- if (!tmp || tmp != domain)
- return tmp;
- }
- }
-
- tmp = dmar_insert_one_dev_info(iommu, bus, devfn, dev, domain);
- if (!tmp || tmp != domain)
- return tmp;
-
- return domain;
-}
-
-static struct dmar_domain *get_domain_for_dev(struct device *dev, int gaw)
-{
- struct dmar_domain *domain, *tmp;
-
- domain = find_domain(dev);
- if (domain)
- goto out;
-
- domain = find_or_alloc_domain(dev, gaw);
- if (!domain)
- goto out;
-
- tmp = set_domain_for_dev(dev, domain);
- if (!tmp || domain != tmp) {
- domain_exit(domain);
- domain = tmp;
- }
-
-out:
-
- return domain;
-}
-
static int iommu_domain_identity_map(struct dmar_domain *domain,
unsigned long long start,
unsigned long long end)
@@ -2742,73 +2630,6 @@ static int iommu_domain_identity_map(struct dmar_domain *domain,
DMA_PTE_READ|DMA_PTE_WRITE);
}

-static int domain_prepare_identity_map(struct device *dev,
- struct dmar_domain *domain,
- unsigned long long start,
- unsigned long long end)
-{
- /* For _hardware_ passthrough, don't bother. But for software
- passthrough, we do it anyway -- it may indicate a memory
- range which is reserved in E820, so which didn't get set
- up to start with in si_domain */
- if (domain == si_domain && hw_pass_through) {
- pr_warn("Ignoring identity map for HW passthrough device %s [0x%Lx - 0x%Lx]\n",
- dev_name(dev), start, end);
- return 0;
- }
-
- pr_info("Setting identity map for device %s [0x%Lx - 0x%Lx]\n",
- dev_name(dev), start, end);
-
- if (end < start) {
- WARN(1, "Your BIOS is broken; RMRR ends before it starts!\n"
- "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
- dmi_get_system_info(DMI_BIOS_VENDOR),
- dmi_get_system_info(DMI_BIOS_VERSION),
- dmi_get_system_info(DMI_PRODUCT_VERSION));
- return -EIO;
- }
-
- if (end >> agaw_to_width(domain->agaw)) {
- WARN(1, "Your BIOS is broken; RMRR exceeds permitted address width (%d bits)\n"
- "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
- agaw_to_width(domain->agaw),
- dmi_get_system_info(DMI_BIOS_VENDOR),
- dmi_get_system_info(DMI_BIOS_VERSION),
- dmi_get_system_info(DMI_PRODUCT_VERSION));
- return -EIO;
- }
-
- return iommu_domain_identity_map(domain, start, end);
-}
-
-static int iommu_prepare_identity_map(struct device *dev,
- unsigned long long start,
- unsigned long long end)
-{
- struct dmar_domain *domain;
- int ret;
-
- domain = get_domain_for_dev(dev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
- if (!domain)
- return -ENOMEM;
-
- ret = domain_prepare_identity_map(dev, domain, start, end);
- if (ret)
- domain_exit(domain);
-
- return ret;
-}
-
-static inline int iommu_prepare_rmrr_dev(struct dmar_rmrr_unit *rmrr,
- struct device *dev)
-{
- if (dev->archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO)
- return 0;
- return iommu_prepare_identity_map(dev, rmrr->base_address,
- rmrr->end_address);
-}
-
static inline struct iommu_resv_region *iommu_get_isa_resv_region(void)
{
if (!isa_resv_region)
@@ -2819,29 +2640,6 @@ static inline struct iommu_resv_region *iommu_get_isa_resv_region(void)
return isa_resv_region;
}

-#ifdef CONFIG_INTEL_IOMMU_FLOPPY_WA
-static inline void iommu_prepare_isa(struct pci_dev *pdev)
-{
- int ret;
- struct iommu_resv_region *reg = iommu_get_isa_resv_region();
-
- if (!reg)
- return;
-
- pr_info("Prepare 0-16MiB unity mapping for LPC\n");
- ret = iommu_prepare_identity_map(&pdev->dev, reg->start,
- reg->start + reg->length - 1);
-
- if (ret)
- pr_err("Failed to create 0-16MiB identity map - floppy might not work\n");
-}
-#else
-static inline void iommu_prepare_isa(struct pci_dev *pdev)
-{
- return;
-}
-#endif /* !CONFIG_INTEL_IOMMU_FLPY_WA */
-
static int md_domain_init(struct dmar_domain *domain, int guest_width);

static int __init si_domain_init(int hw)
@@ -3065,18 +2863,10 @@ static int __init dev_prepare_static_identity_mapping(struct device *dev, int hw

static int __init iommu_prepare_static_identity_mapping(int hw)
{
- struct pci_dev *pdev = NULL;
struct dmar_drhd_unit *drhd;
struct intel_iommu *iommu;
struct device *dev;
- int i;
- int ret = 0;
-
- for_each_pci_dev(pdev) {
- ret = dev_prepare_static_identity_mapping(&pdev->dev, hw);
- if (ret)
- return ret;
- }
+ int i, ret = 0;

for_each_active_iommu(iommu, drhd)
for_each_active_dev_scope(drhd->devices, drhd->devices_cnt, i, dev) {
@@ -3323,12 +3113,9 @@ static int copy_translation_tables(struct intel_iommu *iommu)
static int __init init_dmars(void)
{
struct dmar_drhd_unit *drhd;
- struct dmar_rmrr_unit *rmrr;
bool copied_tables = false;
- struct device *dev;
- struct pci_dev *pdev;
struct intel_iommu *iommu;
- int i, ret;
+ int ret;

/*
* for each drhd
@@ -3482,36 +3269,6 @@ static int __init init_dmars(void)
goto free_iommu;
}
}
- /*
- * For each rmrr
- * for each dev attached to rmrr
- * do
- * locate drhd for dev, alloc domain for dev
- * allocate free domain
- * allocate page table entries for rmrr
- * if context not allocated for bus
- * allocate and init context
- * set present in root table for this bus
- * init context with domain, translation etc
- * endfor
- * endfor
- */
- pr_info("Setting RMRR:\n");
- for_each_rmrr_units(rmrr) {
- /* some BIOS lists non-exist devices in DMAR table. */
- for_each_active_dev_scope(rmrr->devices, rmrr->devices_cnt,
- i, dev) {
- ret = iommu_prepare_rmrr_dev(rmrr, dev);
- if (ret)
- pr_err("Mapping reserved region failed\n");
- }
- }
-
- pdev = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, NULL);
- if (pdev) {
- iommu_prepare_isa(pdev);
- pci_dev_put(pdev);
- }

domains_done:

@@ -3595,53 +3352,6 @@ static unsigned long intel_alloc_iova(struct device *dev,
return iova_pfn;
}

-struct dmar_domain *get_valid_domain_for_dev(struct device *dev)
-{
- struct dmar_domain *domain, *tmp;
- struct dmar_rmrr_unit *rmrr;
- struct device *i_dev;
- int i, ret;
-
- domain = find_domain(dev);
- if (domain)
- goto out;
-
- domain = find_or_alloc_domain(dev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
- if (!domain)
- goto out;
-
- /* We have a new domain - setup possible RMRRs for the device */
- rcu_read_lock();
- for_each_rmrr_units(rmrr) {
- for_each_active_dev_scope(rmrr->devices, rmrr->devices_cnt,
- i, i_dev) {
- if (i_dev != dev)
- continue;
-
- ret = domain_prepare_identity_map(dev, domain,
- rmrr->base_address,
- rmrr->end_address);
- if (ret)
- dev_err(dev, "Mapping reserved region failed\n");
- }
- }
- rcu_read_unlock();
-
- tmp = set_domain_for_dev(dev, domain);
- if (!tmp || domain != tmp) {
- domain_exit(domain);
- domain = tmp;
- }
-
-out:
-
- if (!domain)
- pr_err("Allocating domain for %s failed\n", dev_name(dev));
-
-
- return domain;
-}
-
/* Check if the dev needs to go through non-identity map and unmap process.*/
static int iommu_no_mapping(struct device *dev)
{
@@ -3704,7 +3414,7 @@ static dma_addr_t __intel_map_page(struct device *dev, struct page *page,
if (iommu_no_mapping(dev))
return paddr;

- domain = get_valid_domain_for_dev(dev);
+ domain = find_domain(dev);
if (!domain)
return DMA_MAPPING_ERROR;

@@ -3914,7 +3624,7 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele
if (iommu_no_mapping(dev))
return intel_nontranslate_map_sg(dev, sglist, nelems, dir);

- domain = get_valid_domain_for_dev(dev);
+ domain = find_domain(dev);
if (!domain)
return 0;

@@ -5412,7 +5122,7 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct intel_svm_dev *sd
u64 ctx_lo;
int ret;

- domain = get_valid_domain_for_dev(sdev->dev);
+ domain = find_domain(sdev->dev);
if (!domain)
return -EINVAL;

--
2.17.1
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