[PATCH 8/8] iommu/vt-d: Changes to support kdump
Bill Sumner
bill.sumner at hp.com
Thu Apr 24 17:36:38 PDT 2014
Add "#include <linux/crash_dump.h>" to gain access to is_kdump_kernel()
Modify the operation of the following functions when called during crash dump:
device_to_domain_id
get_domain_for_dev
init_dmars
intel_iommu_init
Signed-off-by: Bill Sumner <bill.sumner at hp.com>
---
drivers/iommu/intel-iommu.c | 133 +++++++++++++++++++++++++++++++++++++++-----
1 file changed, 120 insertions(+), 13 deletions(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 226c1d0..8b3e509 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -46,6 +46,7 @@
#include "irq_remapping.h"
#include "pci.h"
#include "intel-iommu-private.h"
+#include <linux/crash_dump.h>
static LIST_HEAD(dmar_atsr_units);
static LIST_HEAD(dmar_rmrr_units);
@@ -53,6 +54,7 @@ static LIST_HEAD(dmar_rmrr_units);
#define for_each_rmrr_units(rmrr) \
list_for_each_entry(rmrr, &dmar_rmrr_units, list)
+static int intel_iommu_in_crashdump;
static void __init check_tylersburg_isoch(void);
@@ -1796,6 +1798,24 @@ static void domain_remove_dev_info(struct dmar_domain *domain)
spin_unlock_irqrestore(&device_domain_lock, flags);
}
+#ifdef CONFIG_CRASH_DUMP
+static int device_to_domain_id(struct intel_iommu *iommu, u8 bus, u8 devfn)
+{
+ int did = -1; /* domain-id returned */
+ struct root_entry *root;
+ struct context_entry *context;
+ unsigned long flags;
+
+ spin_lock_irqsave(&iommu->lock, flags);
+ root = &iommu->root_entry[bus];
+ context = get_context_addr_from_root(root);
+ if (context && context_present(context+devfn))
+ did = context_get_did(context+devfn);
+ spin_unlock_irqrestore(&iommu->lock, flags);
+ return did;
+}
+#endif /* CONFIG_CRASH_DUMP */
+
/*
* find_domain
* Note: we use struct device->archdata.iommu stores the info
@@ -1880,6 +1900,9 @@ static struct dmar_domain *get_domain_for_dev(struct device *dev, int gaw)
unsigned long flags;
u8 bus, devfn, bridge_bus, bridge_devfn;
int did = -1; /* Default to "no domain_id supplied" */
+#ifdef CONFIG_CRASH_DUMP
+ struct domain_values_entry *dve = NULL;
+#endif /* CONFIG_CRASH_DUMP */
domain = find_domain(dev);
if (domain)
@@ -1920,6 +1943,24 @@ static struct dmar_domain *get_domain_for_dev(struct device *dev, int gaw)
domain = alloc_domain(false);
if (!domain)
goto error;
+
+#ifdef CONFIG_CRASH_DUMP
+ if (intel_iommu_in_crashdump) {
+ /*
+ * if this device had a did in the old kernel
+ * use its values instead of generating new ones
+ */
+ did = device_to_domain_id(iommu, bus, devfn);
+ if (did > 0 || (did == 0 && !cap_caching_mode(iommu->cap)))
+ dve = intel_iommu_did_to_domain_values_entry(did,
+ iommu);
+ if (dve)
+ gaw = dve->gaw;
+ else
+ did = -1;
+ }
+#endif /* CONFIG_CRASH_DUMP */
+
if (iommu_attach_domain(domain, iommu, did)) {
free_domain_mem(domain);
domain = NULL;
@@ -1929,6 +1970,18 @@ static struct dmar_domain *get_domain_for_dev(struct device *dev, int gaw)
if (domain_init(domain, gaw))
goto error;
+#ifdef CONFIG_CRASH_DUMP
+ if (intel_iommu_in_crashdump && dve) {
+
+ if (domain->pgd)
+ free_pgtable_page(domain->pgd);
+
+ domain->pgd = dve->pgd;
+
+ copy_reserved_iova(&dve->iovad, &domain->iovad);
+ }
+#endif /* CONFIG_CRASH_DUMP */
+
/* register pcie-to-pci device */
if (dev_tmp) {
domain = dmar_insert_dev_info(iommu, bridge_bus, bridge_devfn,
@@ -2331,6 +2384,10 @@ static int __init init_dmars(void)
struct device *dev;
struct intel_iommu *iommu;
int i, ret;
+#ifdef CONFIG_CRASH_DUMP
+ struct root_entry *root_old_phys;
+ struct root_entry *root_new_virt;
+#endif /* CONFIG_CRASH_DUMP */
/*
* for each drhd
@@ -2374,16 +2431,40 @@ static int __init init_dmars(void)
if (ret)
goto free_iommu;
- /*
- * TBD:
- * we could share the same root & context tables
- * among all IOMMU's. Need to Split it later.
- */
- ret = iommu_alloc_root_entry(iommu);
- if (ret) {
- printk(KERN_ERR "IOMMU: allocate root entry failed\n");
- goto free_iommu;
+#ifdef CONFIG_CRASH_DUMP
+ if (intel_iommu_in_crashdump) {
+ pr_info("IOMMU Copying translate tables from panicked kernel\n");
+ ret = intel_iommu_copy_translation_tables(drhd,
+ &root_old_phys, &root_new_virt,
+ g_num_of_iommus);
+ if (ret) {
+ pr_err("IOMMU: Copy translate tables failed\n");
+
+ /* Best to stop trying */
+ intel_iommu_in_crashdump = false;
+ goto error;
+ }
+ iommu->root_entry = root_new_virt;
+ pr_info("IOMMU: root_new_virt:0x%12.12llx phys:0x%12.12llx\n",
+ (u64)root_new_virt,
+ virt_to_phys(root_new_virt));
+ intel_iommu_get_dids_from_old_kernel(iommu);
+ } else {
+#endif /* CONFIG_CRASH_DUMP */
+ /*
+ * TBD:
+ * we could share the same root & context tables
+ * among all IOMMU's. Need to Split it later.
+ */
+ ret = iommu_alloc_root_entry(iommu);
+ if (ret) {
+ printk(KERN_ERR "IOMMU: allocate root entry failed\n");
+ goto free_iommu;
+ }
+#ifdef CONFIG_CRASH_DUMP
}
+#endif /* CONFIG_CRASH_DUMP */
+
if (!ecap_pass_through(iommu->ecap))
hw_pass_through = 0;
}
@@ -2442,6 +2523,16 @@ static int __init init_dmars(void)
check_tylersburg_isoch();
+#ifdef CONFIG_CRASH_DUMP
+ /*
+ * In the crashdump kernel: Skip setting-up new domains for
+ * si, rmrr, and the isa bus on the expectation that these
+ * translations were copied from the old kernel.
+ */
+ if (intel_iommu_in_crashdump)
+ goto skip_new_domains_for_si_rmrr_isa;
+#endif /* CONFIG_CRASH_DUMP */
+
/*
* If pass through is not set or not enabled, setup context entries for
* identity mappings for rmrr, gfx, and isa and may fall back to static
@@ -2482,6 +2573,10 @@ static int __init init_dmars(void)
iommu_prepare_isa();
+#ifdef CONFIG_CRASH_DUMP
+skip_new_domains_for_si_rmrr_isa:;
+#endif /* CONFIG_CRASH_DUMP */
+
/*
* for each drhd
* enable fault log
@@ -3624,12 +3719,24 @@ int __init intel_iommu_init(void)
goto out_free_dmar;
}
+#ifdef CONFIG_CRASH_DUMP
/*
- * Disable translation if already enabled prior to OS handover.
+ * If (This is the crash kernel)
+ * Set: copy iommu translate tables from old kernel
+ * Skip disabling the iommu hardware translations
*/
- for_each_active_iommu(iommu, drhd)
- if (iommu->gcmd & DMA_GCMD_TE)
- iommu_disable_translation(iommu);
+ if (is_kdump_kernel()) {
+ intel_iommu_in_crashdump = true;
+ pr_info("IOMMU intel_iommu_in_crashdump = true\n");
+ pr_info("IOMMU Skip disabling iommu hardware translations\n");
+ } else
+#endif /* CONFIG_CRASH_DUMP */
+ /*
+ * Disable translation if already enabled prior to OS handover.
+ */
+ for_each_active_iommu(iommu, drhd)
+ if (iommu->gcmd & DMA_GCMD_TE)
+ iommu_disable_translation(iommu);
if (dmar_dev_scope_init() < 0) {
if (force_on)
--
Bill Sumner <bill.sumner at hp.com>
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