From: Jan Beulich <jbeulich@suse.com>
Subject: IOMMU: also pass p2m_access_t to p2m_get_iommu_flags()
A subsequent change will want to customize the IOMMU permissions based
on this.
This is part of XSA-378.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Paul Durrant <paul@xen.org>
--- a/xen/arch/x86/mm/p2m-ept.c
+++ b/xen/arch/x86/mm/p2m-ept.c
@@ -681,7 +681,7 @@ ept_set_entry(struct p2m_domain *p2m, gf
uint8_t ipat = 0;
bool_t need_modify_vtd_table = 1;
bool_t vtd_pte_present = 0;
- unsigned int iommu_flags = p2m_get_iommu_flags(p2mt, mfn);
+ unsigned int iommu_flags = p2m_get_iommu_flags(p2mt, p2ma, mfn);
bool_t needs_sync = 1;
ept_entry_t old_entry = { .epte = 0 };
ept_entry_t new_entry = { .epte = 0 };
@@ -809,8 +809,8 @@ ept_set_entry(struct p2m_domain *p2m, gf
/* Safe to read-then-write because we hold the p2m lock */
if ( ept_entry->mfn == new_entry.mfn &&
- p2m_get_iommu_flags(ept_entry->sa_p2mt, _mfn(ept_entry->mfn)) ==
- iommu_flags )
+ p2m_get_iommu_flags(ept_entry->sa_p2mt, ept_entry->access,
+ _mfn(ept_entry->mfn)) == iommu_flags )
need_modify_vtd_table = 0;
ept_p2m_type_to_flags(p2m, &new_entry);
--- a/xen/arch/x86/mm/p2m-pt.c
+++ b/xen/arch/x86/mm/p2m-pt.c
@@ -545,6 +545,16 @@ int p2m_pt_handle_deferred_changes(uint6
return rc;
}
+/* Reconstruct a fake p2m_access_t from stored PTE flags. */
+static p2m_access_t p2m_flags_to_access(unsigned int flags)
+{
+ if ( flags & _PAGE_PRESENT )
+ return p2m_access_n;
+
+ /* No need to look at _PAGE_NX for now. */
+ return flags & _PAGE_RW ? p2m_access_rw : p2m_access_r;
+}
+
/* Checks only applicable to entries with order > PAGE_ORDER_4K */
static void check_entry(mfn_t mfn, p2m_type_t new, p2m_type_t old,
unsigned int order)
@@ -579,7 +589,7 @@ p2m_pt_set_entry(struct p2m_domain *p2m,
l2_pgentry_t l2e_content;
l3_pgentry_t l3e_content;
int rc;
- unsigned int iommu_pte_flags = p2m_get_iommu_flags(p2mt, mfn);
+ unsigned int iommu_pte_flags = p2m_get_iommu_flags(p2mt, p2ma, mfn);
/*
* old_mfn and iommu_old_flags control possible flush/update needs on the
* IOMMU: We need to flush when MFN or flags (i.e. permissions) change.
@@ -642,6 +652,7 @@ p2m_pt_set_entry(struct p2m_domain *p2m,
old_mfn = l1e_get_pfn(*p2m_entry);
iommu_old_flags =
p2m_get_iommu_flags(p2m_flags_to_type(flags),
+ p2m_flags_to_access(flags),
_mfn(old_mfn));
}
else
@@ -684,9 +695,10 @@ p2m_pt_set_entry(struct p2m_domain *p2m,
0, L1_PAGETABLE_ENTRIES);
ASSERT(p2m_entry);
old_mfn = l1e_get_pfn(*p2m_entry);
+ flags = l1e_get_flags(*p2m_entry);
iommu_old_flags =
- p2m_get_iommu_flags(p2m_flags_to_type(l1e_get_flags(*p2m_entry)),
- _mfn(old_mfn));
+ p2m_get_iommu_flags(p2m_flags_to_type(flags),
+ p2m_flags_to_access(flags), _mfn(old_mfn));
if ( mfn_valid(mfn) || p2m_allows_invalid_mfn(p2mt) )
entry_content = p2m_l1e_from_pfn(mfn_x(mfn),
@@ -714,6 +726,7 @@ p2m_pt_set_entry(struct p2m_domain *p2m,
old_mfn = l1e_get_pfn(*p2m_entry);
iommu_old_flags =
p2m_get_iommu_flags(p2m_flags_to_type(flags),
+ p2m_flags_to_access(flags),
_mfn(old_mfn));
}
else
--- a/xen/include/asm-x86/p2m.h
+++ b/xen/include/asm-x86/p2m.h
@@ -915,7 +915,8 @@ static inline void p2m_altp2m_check(stru
/*
* p2m type to IOMMU flags
*/
-static inline unsigned int p2m_get_iommu_flags(p2m_type_t p2mt, mfn_t mfn)
+static inline unsigned int p2m_get_iommu_flags(p2m_type_t p2mt,
+ p2m_access_t p2ma, mfn_t mfn)
{
unsigned int flags;