While the flush coalescing optimization has been helping the non-shared
case, it has actually lead to double flushes in the shared case (which
ought to be the more common one nowadays at least): Once from
*_set_entry() and a second time up the call tree from wherever the
overriding flag gets played with. In alignment with XSA-346 suppress
flushing in this case.
Similarly avoid excessive setting of IOMMU_FLUSHF_added on the batched
flushes: "idx" hasn't been added a new mapping for.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
TBD: The Arm part really is just for completeness (and hence could also
be dropped) - the affected mapping spaces aren't currently
supported there.
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -1045,7 +1045,7 @@ static int __p2m_set_entry(struct p2m_do
p2m->lowest_mapped_gfn = gfn_min(p2m->lowest_mapped_gfn, sgfn);
}
- if ( is_iommu_enabled(p2m->domain) &&
+ if ( is_iommu_enabled(p2m->domain) && !this_cpu(iommu_dont_flush_iotlb) &&
(lpae_is_valid(orig_pte) || lpae_is_valid(*entry)) )
{
unsigned int flush_flags = 0;
--- a/xen/arch/x86/mm/p2m-ept.c
+++ b/xen/arch/x86/mm/p2m-ept.c
@@ -842,7 +842,7 @@ out:
if ( rc == 0 && p2m_is_hostp2m(p2m) &&
need_modify_vtd_table )
{
- if ( iommu_use_hap_pt(d) )
+ if ( iommu_use_hap_pt(d) && !this_cpu(iommu_dont_flush_iotlb) )
rc = iommu_iotlb_flush(d, _dfn(gfn), 1ul << order,
(iommu_flags ? IOMMU_FLUSHF_added : 0) |
(vtd_pte_present ? IOMMU_FLUSHF_modified
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -870,7 +870,7 @@ int xenmem_add_to_physmap(struct domain
this_cpu(iommu_dont_flush_iotlb) = 0;
ret = iommu_iotlb_flush(d, _dfn(xatp->idx - done), done,
- IOMMU_FLUSHF_added | IOMMU_FLUSHF_modified);
+ IOMMU_FLUSHF_modified);
if ( unlikely(ret) && rc >= 0 )
rc = ret;
case, it has actually lead to double flushes in the shared case (which
ought to be the more common one nowadays at least): Once from
*_set_entry() and a second time up the call tree from wherever the
overriding flag gets played with. In alignment with XSA-346 suppress
flushing in this case.
Similarly avoid excessive setting of IOMMU_FLUSHF_added on the batched
flushes: "idx" hasn't been added a new mapping for.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
---
TBD: The Arm part really is just for completeness (and hence could also
be dropped) - the affected mapping spaces aren't currently
supported there.
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -1045,7 +1045,7 @@ static int __p2m_set_entry(struct p2m_do
p2m->lowest_mapped_gfn = gfn_min(p2m->lowest_mapped_gfn, sgfn);
}
- if ( is_iommu_enabled(p2m->domain) &&
+ if ( is_iommu_enabled(p2m->domain) && !this_cpu(iommu_dont_flush_iotlb) &&
(lpae_is_valid(orig_pte) || lpae_is_valid(*entry)) )
{
unsigned int flush_flags = 0;
--- a/xen/arch/x86/mm/p2m-ept.c
+++ b/xen/arch/x86/mm/p2m-ept.c
@@ -842,7 +842,7 @@ out:
if ( rc == 0 && p2m_is_hostp2m(p2m) &&
need_modify_vtd_table )
{
- if ( iommu_use_hap_pt(d) )
+ if ( iommu_use_hap_pt(d) && !this_cpu(iommu_dont_flush_iotlb) )
rc = iommu_iotlb_flush(d, _dfn(gfn), 1ul << order,
(iommu_flags ? IOMMU_FLUSHF_added : 0) |
(vtd_pte_present ? IOMMU_FLUSHF_modified
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -870,7 +870,7 @@ int xenmem_add_to_physmap(struct domain
this_cpu(iommu_dont_flush_iotlb) = 0;
ret = iommu_iotlb_flush(d, _dfn(xatp->idx - done), done,
- IOMMU_FLUSHF_added | IOMMU_FLUSHF_modified);
+ IOMMU_FLUSHF_modified);
if ( unlikely(ret) && rc >= 0 )
rc = ret;