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Commit eb791aa7 authored by Joerg Roedel's avatar Joerg Roedel
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iommu/amd: Fix race in increase_address_space()/fetch_pte() 

The 'pt_root' and 'mode' struct members of 'struct protection_domain'
need to be get/set atomically, otherwise the page-table of the domain
can get corrupted.

Merge the fields into one atomic64_t struct member which can be
get/set atomically.

Fixes: 92d420ec ("iommu/amd: Relax locking in dma_ops path")
Reported-by: default avatarQian Cai <cai@lca.pw>
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
Tested-by: default avatarQian Cai <cai@lca.pw>
Link: https://lore.kernel.org/r/20200504125413.16798-2-joro@8bytes.orgSigned-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 0e698dfa
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Showing with 112 additions and 37 deletions
drivers/iommu/amd_iommu.c
View file @ eb791aa7
......@@ -151,6 +151,26 @@ static struct protection_domain *to_pdomain(struct iommu_domain *dom)
return container_of(dom, struct protection_domain, domain);
}
static void amd_iommu_domain_get_pgtable(struct protection_domain *domain,
struct domain_pgtable *pgtable)
{
u64 pt_root = atomic64_read(&domain->pt_root);
pgtable->root = (u64 *)(pt_root & PAGE_MASK);
pgtable->mode = pt_root & 7; /* lowest 3 bits encode pgtable mode */
}
static u64 amd_iommu_domain_encode_pgtable(u64 *root, int mode)
{
u64 pt_root;
/* lowest 3 bits encode pgtable mode */
pt_root = mode & 7;
pt_root |= (u64)root;
return pt_root;
}
static struct iommu_dev_data *alloc_dev_data(u16 devid)
{
struct iommu_dev_data *dev_data;
......@@ -1397,13 +1417,18 @@ static struct page *free_sub_pt(unsigned long root, int mode,
static void free_pagetable(struct protection_domain *domain)
{
unsigned long root = (unsigned long)domain->pt_root;
struct domain_pgtable pgtable;
struct page *freelist = NULL;
unsigned long root;
amd_iommu_domain_get_pgtable(domain, &pgtable);
atomic64_set(&domain->pt_root, 0);
BUG_ON(domain->mode < PAGE_MODE_NONE ||
domain->mode > PAGE_MODE_6_LEVEL);
BUG_ON(pgtable.mode < PAGE_MODE_NONE ||
pgtable.mode > PAGE_MODE_6_LEVEL);
freelist = free_sub_pt(root, domain->mode, freelist);
root = (unsigned long)pgtable.root;
freelist = free_sub_pt(root, pgtable.mode, freelist);
free_page_list(freelist);
}
......@@ -1417,24 +1442,28 @@ static bool increase_address_space(struct protection_domain *domain,
unsigned long address,
gfp_t gfp)
{
struct domain_pgtable pgtable;
unsigned long flags;
bool ret = false;
u64 *pte;
u64 *pte, root;
spin_lock_irqsave(&domain->lock, flags);
if (address <= PM_LEVEL_SIZE(domain->mode) ||
WARN_ON_ONCE(domain->mode == PAGE_MODE_6_LEVEL))
amd_iommu_domain_get_pgtable(domain, &pgtable);
if (address <= PM_LEVEL_SIZE(pgtable.mode) ||
WARN_ON_ONCE(pgtable.mode == PAGE_MODE_6_LEVEL))
goto out;
pte = (void *)get_zeroed_page(gfp);
if (!pte)
goto out;
*pte = PM_LEVEL_PDE(domain->mode,
iommu_virt_to_phys(domain->pt_root));
domain->pt_root = pte;
domain->mode += 1;
*pte = PM_LEVEL_PDE(pgtable.mode, iommu_virt_to_phys(pgtable.root));
root = amd_iommu_domain_encode_pgtable(pte, pgtable.mode + 1);
atomic64_set(&domain->pt_root, root);
ret = true;
......@@ -1451,16 +1480,22 @@ static u64 *alloc_pte(struct protection_domain *domain,
gfp_t gfp,
bool *updated)
{
struct domain_pgtable pgtable;
int level, end_lvl;
u64 *pte, *page;
BUG_ON(!is_power_of_2(page_size));
while (address > PM_LEVEL_SIZE(domain->mode))
amd_iommu_domain_get_pgtable(domain, &pgtable);
while (address > PM_LEVEL_SIZE(pgtable.mode)) {
*updated = increase_address_space(domain, address, gfp) || *updated;
amd_iommu_domain_get_pgtable(domain, &pgtable);
}
level = domain->mode - 1;
pte = &domain->pt_root[PM_LEVEL_INDEX(level, address)];
level = pgtable.mode - 1;
pte = &pgtable.root[PM_LEVEL_INDEX(level, address)];
address = PAGE_SIZE_ALIGN(address, page_size);
end_lvl = PAGE_SIZE_LEVEL(page_size);
......@@ -1536,16 +1571,19 @@ static u64 *fetch_pte(struct protection_domain *domain,
unsigned long address,
unsigned long *page_size)
{
struct domain_pgtable pgtable;
int level;
u64 *pte;
*page_size = 0;
if (address > PM_LEVEL_SIZE(domain->mode))
amd_iommu_domain_get_pgtable(domain, &pgtable);
if (address > PM_LEVEL_SIZE(pgtable.mode))
return NULL;
level = domain->mode - 1;
pte = &domain->pt_root[PM_LEVEL_INDEX(level, address)];
level = pgtable.mode - 1;
pte = &pgtable.root[PM_LEVEL_INDEX(level, address)];
*page_size = PTE_LEVEL_PAGE_SIZE(level);
while (level > 0) {
......@@ -1806,6 +1844,7 @@ static void dma_ops_domain_free(struct protection_domain *domain)
static struct protection_domain *dma_ops_domain_alloc(void)
{
struct protection_domain *domain;
u64 *pt_root, root;
domain = kzalloc(sizeof(struct protection_domain), GFP_KERNEL);
if (!domain)
......@@ -1814,12 +1853,14 @@ static struct protection_domain *dma_ops_domain_alloc(void)
if (protection_domain_init(domain))
goto free_domain;
domain->mode = PAGE_MODE_3_LEVEL;
domain->pt_root = (void *)get_zeroed_page(GFP_KERNEL);
domain->flags = PD_DMA_OPS_MASK;
if (!domain->pt_root)
pt_root = (void *)get_zeroed_page(GFP_KERNEL);
if (!pt_root)
goto free_domain;
root = amd_iommu_domain_encode_pgtable(pt_root, PAGE_MODE_3_LEVEL);
atomic64_set(&domain->pt_root, root);
domain->flags = PD_DMA_OPS_MASK;
if (iommu_get_dma_cookie(&domain->domain) == -ENOMEM)
goto free_domain;
......@@ -1843,14 +1884,17 @@ static bool dma_ops_domain(struct protection_domain *domain)
static void set_dte_entry(u16 devid, struct protection_domain *domain,
bool ats, bool ppr)
{
struct domain_pgtable pgtable;
u64 pte_root = 0;
u64 flags = 0;
u32 old_domid;
if (domain->mode != PAGE_MODE_NONE)
pte_root = iommu_virt_to_phys(domain->pt_root);
amd_iommu_domain_get_pgtable(domain, &pgtable);
if (pgtable.mode != PAGE_MODE_NONE)
pte_root = iommu_virt_to_phys(pgtable.root);
pte_root |= (domain->mode & DEV_ENTRY_MODE_MASK)
pte_root |= (pgtable.mode & DEV_ENTRY_MODE_MASK)
<< DEV_ENTRY_MODE_SHIFT;
pte_root |= DTE_FLAG_IR | DTE_FLAG_IW | DTE_FLAG_V | DTE_FLAG_TV;
......@@ -2375,6 +2419,7 @@ static struct protection_domain *protection_domain_alloc(void)
static struct iommu_domain *amd_iommu_domain_alloc(unsigned type)
{
struct protection_domain *pdomain;
u64 *pt_root, root;
switch (type) {
case IOMMU_DOMAIN_UNMANAGED:
......@@ -2382,13 +2427,15 @@ static struct iommu_domain *amd_iommu_domain_alloc(unsigned type)
if (!pdomain)
return NULL;
pdomain->mode = PAGE_MODE_3_LEVEL;
pdomain->pt_root = (void *)get_zeroed_page(GFP_KERNEL);
if (!pdomain->pt_root) {
pt_root = (void *)get_zeroed_page(GFP_KERNEL);
if (!pt_root) {
protection_domain_free(pdomain);
return NULL;
}
root = amd_iommu_domain_encode_pgtable(pt_root, PAGE_MODE_3_LEVEL);
atomic64_set(&pdomain->pt_root, root);
pdomain->domain.geometry.aperture_start = 0;
pdomain->domain.geometry.aperture_end = ~0ULL;
pdomain->domain.geometry.force_aperture = true;
......@@ -2406,7 +2453,7 @@ static struct iommu_domain *amd_iommu_domain_alloc(unsigned type)
if (!pdomain)
return NULL;
pdomain->mode = PAGE_MODE_NONE;
atomic64_set(&pdomain->pt_root, PAGE_MODE_NONE);
break;
default:
return NULL;
......@@ -2418,6 +2465,7 @@ static struct iommu_domain *amd_iommu_domain_alloc(unsigned type)
static void amd_iommu_domain_free(struct iommu_domain *dom)
{
struct protection_domain *domain;
struct domain_pgtable pgtable;
domain = to_pdomain(dom);
......@@ -2435,7 +2483,9 @@ static void amd_iommu_domain_free(struct iommu_domain *dom)
dma_ops_domain_free(domain);
break;
default:
if (domain->mode != PAGE_MODE_NONE)
amd_iommu_domain_get_pgtable(domain, &pgtable);
if (pgtable.mode != PAGE_MODE_NONE)
free_pagetable(domain);
if (domain->flags & PD_IOMMUV2_MASK)
......@@ -2518,10 +2568,12 @@ static int amd_iommu_map(struct iommu_domain *dom, unsigned long iova,
gfp_t gfp)
{
struct protection_domain *domain = to_pdomain(dom);
struct domain_pgtable pgtable;
int prot = 0;
int ret;
if (domain->mode == PAGE_MODE_NONE)
amd_iommu_domain_get_pgtable(domain, &pgtable);
if (pgtable.mode == PAGE_MODE_NONE)
return -EINVAL;
if (iommu_prot & IOMMU_READ)
......@@ -2541,8 +2593,10 @@ static size_t amd_iommu_unmap(struct iommu_domain *dom, unsigned long iova,
struct iommu_iotlb_gather *gather)
{
struct protection_domain *domain = to_pdomain(dom);
struct domain_pgtable pgtable;
if (domain->mode == PAGE_MODE_NONE)
amd_iommu_domain_get_pgtable(domain, &pgtable);
if (pgtable.mode == PAGE_MODE_NONE)
return 0;
return iommu_unmap_page(domain, iova, page_size);
......@@ -2553,9 +2607,11 @@ static phys_addr_t amd_iommu_iova_to_phys(struct iommu_domain *dom,
{
struct protection_domain *domain = to_pdomain(dom);
unsigned long offset_mask, pte_pgsize;
struct domain_pgtable pgtable;
u64 *pte, __pte;
if (domain->mode == PAGE_MODE_NONE)
amd_iommu_domain_get_pgtable(domain, &pgtable);
if (pgtable.mode == PAGE_MODE_NONE)
return iova;
pte = fetch_pte(domain, iova, &pte_pgsize);
......@@ -2708,16 +2764,26 @@ EXPORT_SYMBOL(amd_iommu_unregister_ppr_notifier);
void amd_iommu_domain_direct_map(struct iommu_domain *dom)
{
struct protection_domain *domain = to_pdomain(dom);
struct domain_pgtable pgtable;
unsigned long flags;
u64 pt_root;
spin_lock_irqsave(&domain->lock, flags);
/* First save pgtable configuration*/
amd_iommu_domain_get_pgtable(domain, &pgtable);
/* Update data structure */
domain->mode = PAGE_MODE_NONE;
pt_root = amd_iommu_domain_encode_pgtable(NULL, PAGE_MODE_NONE);
atomic64_set(&domain->pt_root, pt_root);
/* Make changes visible to IOMMUs */
update_domain(domain);
/* Restore old pgtable in domain->ptroot to free page-table */
pt_root = amd_iommu_domain_encode_pgtable(pgtable.root, pgtable.mode);
atomic64_set(&domain->pt_root, pt_root);
/* Page-table is not visible to IOMMU anymore, so free it */
free_pagetable(domain);
......@@ -2908,9 +2974,11 @@ static u64 *__get_gcr3_pte(u64 *root, int level, int pasid, bool alloc)
static int __set_gcr3(struct protection_domain *domain, int pasid,
unsigned long cr3)
{
struct domain_pgtable pgtable;
u64 *pte;
if (domain->mode != PAGE_MODE_NONE)
amd_iommu_domain_get_pgtable(domain, &pgtable);
if (pgtable.mode != PAGE_MODE_NONE)
return -EINVAL;
pte = __get_gcr3_pte(domain->gcr3_tbl, domain->glx, pasid, true);
......@@ -2924,9 +2992,11 @@ static int __set_gcr3(struct protection_domain *domain, int pasid,
static int __clear_gcr3(struct protection_domain *domain, int pasid)
{
struct domain_pgtable pgtable;
u64 *pte;
if (domain->mode != PAGE_MODE_NONE)
amd_iommu_domain_get_pgtable(domain, &pgtable);
if (pgtable.mode != PAGE_MODE_NONE)
return -EINVAL;
pte = __get_gcr3_pte(domain->gcr3_tbl, domain->glx, pasid, false);
......
drivers/iommu/amd_iommu_types.h
View file @ eb791aa7
......@@ -468,8 +468,7 @@ struct protection_domain {
iommu core code */
spinlock_t lock; /* mostly used to lock the page table*/
u16 id; /* the domain id written to the device table */
int mode; /* paging mode (0-6 levels) */
u64 *pt_root; /* page table root pointer */
atomic64_t pt_root; /* pgtable root and pgtable mode */
int glx; /* Number of levels for GCR3 table */
u64 *gcr3_tbl; /* Guest CR3 table */
unsigned long flags; /* flags to find out type of domain */
......@@ -477,6 +476,12 @@ struct protection_domain {
unsigned dev_iommu[MAX_IOMMUS]; /* per-IOMMU reference count */
};
/* For decocded pt_root */
struct domain_pgtable {
int mode;
u64 *root;
};
/*
* Structure where we save information about one hardware AMD IOMMU in the
* system.
......
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