[PATCH 5/5] iommu/amd: Do not flush Device Table in iommu_map_page()

Joerg Roedel
2020-05-04T12:54:25Z

The flush of the Device Table Entries for the domain has already
happened in increase_address_space(), if necessary. Do no flush them
again in iommu_map_page().

Tested-by: Qian Cai <cai@lca.pw>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
---
drivers/iommu/amd_iommu.c | 27 ++++++++++++++++-----------
1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 2ae1daac888a..1dc3718560d0 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1446,15 +1446,18 @@ static bool increase_address_space(struct protection_domain *domain,
{
struct domain_pgtable pgtable;
unsigned long flags;
- bool ret = false;
+ bool ret = true;
u64 *pte, root;

spin_lock_irqsave(&domain->lock, flags);

amd_iommu_domain_get_pgtable(domain, &pgtable);

- if (address <= PM_LEVEL_SIZE(pgtable.mode) ||
- WARN_ON_ONCE(pgtable.mode == PAGE_MODE_6_LEVEL))
+ if (address <= PM_LEVEL_SIZE(pgtable.mode))
+ goto out;
+
+ ret = false;
+ if (WARN_ON_ONCE(pgtable.mode == PAGE_MODE_6_LEVEL))
goto out;

pte = (void *)get_zeroed_page(gfp);
@@ -1499,19 +1502,15 @@ static u64 *alloc_pte(struct protection_domain *domain,
amd_iommu_domain_get_pgtable(domain, &pgtable);

while (address > PM_LEVEL_SIZE(pgtable.mode)) {
- bool upd = increase_address_space(domain, address, gfp);
-
- /* Read new values to check if update was successful */
- amd_iommu_domain_get_pgtable(domain, &pgtable);
-
/*
* Return an error if there is no memory to update the
* page-table.
*/
- if (!upd && (address > PM_LEVEL_SIZE(pgtable.mode)))
+ if (!increase_address_space(domain, address, gfp))
return NULL;

- *updated = *updated || upd;
+ /* Read new values to check if update was successful */
+ amd_iommu_domain_get_pgtable(domain, &pgtable);
}

@@ -1719,7 +1718,13 @@ static int iommu_map_page(struct protection_domain *dom,
unsigned long flags;

spin_lock_irqsave(&dom->lock, flags);
- update_domain(dom);
+ /*
+ * Flush domain TLB(s) and wait for completion. Any Device-Table
+ * Updates and flushing already happened in
+ * increase_address_space().
+ */
+ domain_flush_tlb_pde(dom);
+ domain_flush_complete(dom);
spin_unlock_irqrestore(&dom->lock, flags);