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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen master] AMD-Vi: allocate root table on demand
commit 8709b10c7f667ee6c3b76a5ef6a469e096f27502
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon Mar 20 17:00:34 2017 +0100
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Mar 20 17:00:34 2017 +0100
AMD-Vi: allocate root table on demand
This was my originally intended fix for the AMD side of XSA-207:
There's no need to unconditionally allocate the root table, and with
that there's then also no way to leak it when a guest has no devices
assigned.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Acked-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
---
xen/drivers/passthrough/amd/iommu_map.c | 20 ++++++++++---
xen/drivers/passthrough/amd/pci_amd_iommu.c | 42 +++++++++++++--------------
xen/include/asm-x86/hvm/svm/amd-iommu-proto.h | 1 +
3 files changed, 38 insertions(+), 25 deletions(-)
diff --git a/xen/drivers/passthrough/amd/iommu_map.c
b/xen/drivers/passthrough/amd/iommu_map.c
index 67ba145..fd2327d 100644
--- a/xen/drivers/passthrough/amd/iommu_map.c
+++ b/xen/drivers/passthrough/amd/iommu_map.c
@@ -636,11 +636,10 @@ int amd_iommu_map_page(struct domain *d, unsigned long
gfn, unsigned long mfn,
{
bool_t need_flush = 0;
struct domain_iommu *hd = dom_iommu(d);
+ int rc;
unsigned long pt_mfn[7];
unsigned int merge_level;
- BUG_ON( !hd->arch.root_table );
-
if ( iommu_use_hap_pt(d) )
return 0;
@@ -648,6 +647,15 @@ int amd_iommu_map_page(struct domain *d, unsigned long
gfn, unsigned long mfn,
spin_lock(&hd->arch.mapping_lock);
+ rc = amd_iommu_alloc_root(hd);
+ if ( rc )
+ {
+ spin_unlock(&hd->arch.mapping_lock);
+ AMD_IOMMU_DEBUG("Root table alloc failed, gfn = %lx\n", gfn);
+ domain_crash(d);
+ return rc;
+ }
+
/* Since HVM domain is initialized with 2 level IO page table,
* we might need a deeper page table for lager gfn now */
if ( is_hvm_domain(d) )
@@ -717,8 +725,6 @@ int amd_iommu_unmap_page(struct domain *d, unsigned long
gfn)
unsigned long pt_mfn[7];
struct domain_iommu *hd = dom_iommu(d);
- BUG_ON( !hd->arch.root_table );
-
if ( iommu_use_hap_pt(d) )
return 0;
@@ -726,6 +732,12 @@ int amd_iommu_unmap_page(struct domain *d, unsigned long
gfn)
spin_lock(&hd->arch.mapping_lock);
+ if ( !hd->arch.root_table )
+ {
+ spin_unlock(&hd->arch.mapping_lock);
+ return 0;
+ }
+
/* Since HVM domain is initialized with 2 level IO page table,
* we might need a deeper page table for lager gfn now */
if ( is_hvm_domain(d) )
diff --git a/xen/drivers/passthrough/amd/pci_amd_iommu.c
b/xen/drivers/passthrough/amd/pci_amd_iommu.c
index b2428f8..8c25110 100644
--- a/xen/drivers/passthrough/amd/pci_amd_iommu.c
+++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c
@@ -222,23 +222,29 @@ int __init amd_iov_detect(void)
return scan_pci_devices();
}
-static int allocate_domain_resources(struct domain_iommu *hd)
+int amd_iommu_alloc_root(struct domain_iommu *hd)
{
- /* allocate root table */
- spin_lock(&hd->arch.mapping_lock);
- if ( !hd->arch.root_table )
+ if ( unlikely(!hd->arch.root_table) )
{
hd->arch.root_table = alloc_amd_iommu_pgtable();
if ( !hd->arch.root_table )
- {
- spin_unlock(&hd->arch.mapping_lock);
return -ENOMEM;
- }
}
- spin_unlock(&hd->arch.mapping_lock);
+
return 0;
}
+static int __must_check allocate_domain_resources(struct domain_iommu *hd)
+{
+ int rc;
+
+ spin_lock(&hd->arch.mapping_lock);
+ rc = amd_iommu_alloc_root(hd);
+ spin_unlock(&hd->arch.mapping_lock);
+
+ return rc;
+}
+
static int get_paging_mode(unsigned long entries)
{
int level = 1;
@@ -259,14 +265,6 @@ static int amd_iommu_domain_init(struct domain *d)
{
struct domain_iommu *hd = dom_iommu(d);
- /* allocate page directroy */
- if ( allocate_domain_resources(hd) != 0 )
- {
- if ( hd->arch.root_table )
- free_domheap_page(hd->arch.root_table);
- return -ENOMEM;
- }
-
/* For pv and dom0, stick with get_paging_mode(max_page)
* For HVM dom0, use 2 level page table at first */
hd->arch.paging_mode = is_hvm_domain(d) ?
@@ -280,6 +278,9 @@ static void __hwdom_init amd_iommu_hwdom_init(struct domain
*d)
unsigned long i;
const struct amd_iommu *iommu;
+ if ( allocate_domain_resources(dom_iommu(d)) )
+ BUG();
+
if ( !iommu_passthrough && !need_iommu(d) )
{
int rc = 0;
@@ -363,7 +364,7 @@ static int reassign_device(struct domain *source, struct
domain *target,
u8 devfn, struct pci_dev *pdev)
{
struct amd_iommu *iommu;
- int bdf;
+ int bdf, rc;
struct domain_iommu *t = dom_iommu(target);
bdf = PCI_BDF2(pdev->bus, pdev->devfn);
@@ -385,10 +386,9 @@ static int reassign_device(struct domain *source, struct
domain *target,
pdev->domain = target;
}
- /* IO page tables might be destroyed after pci-detach the last device
- * In this case, we have to re-allocate root table for next pci-attach.*/
- if ( t->arch.root_table == NULL )
- allocate_domain_resources(t);
+ rc = allocate_domain_resources(t);
+ if ( rc )
+ return rc;
amd_iommu_setup_domain_device(target, iommu, devfn, pdev);
AMD_IOMMU_DEBUG("Re-assign %04x:%02x:%02x.%u from dom%d to dom%d\n",
diff --git a/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h
b/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h
index 1cf9c3d..99bc21c 100644
--- a/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h
+++ b/xen/include/asm-x86/hvm/svm/amd-iommu-proto.h
@@ -56,6 +56,7 @@ int __must_check amd_iommu_map_page(struct domain *d,
unsigned long gfn,
unsigned long mfn, unsigned int flags);
int __must_check amd_iommu_unmap_page(struct domain *d, unsigned long gfn);
u64 amd_iommu_get_next_table_from_pte(u32 *entry);
+int __must_check amd_iommu_alloc_root(struct domain_iommu *hd);
int amd_iommu_reserve_domain_unity_map(struct domain *domain,
u64 phys_addr, unsigned long size,
int iw, int ir);
--
generated by git-patchbot for /home/xen/git/xen.git#master
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