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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 6/7] x86/mm: Combine {destroy, replace}_grant_{pte, va}_mapping()
As with the create side of things, these are largely identical. Most cases
are actually destroying the mapping rather than replacing it with a stolen
entry.
Reimplement their logic in replace_grant_pv_mapping() in a mostly common
way.
No (intended) change in behaviour from a guests point of view.
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
---
xen/arch/x86/mm.c | 277 +++++++++++++++++-------------------------------------
1 file changed, 87 insertions(+), 190 deletions(-)
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index afd98d9..1a8ad42 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -3831,183 +3831,6 @@ static unsigned int grant_to_pte_flags(unsigned int
grant_flags,
return pte_flags;
}
-static int destroy_grant_pte_mapping(
- uint64_t addr, unsigned long frame, unsigned int grant_pte_flags,
- struct domain *d)
-{
- int rc = GNTST_okay;
- void *va;
- unsigned long gmfn, mfn;
- struct page_info *page;
- l1_pgentry_t ol1e;
-
- /*
- * addr comes from Xen's active_entry tracking so isn't guest controlled,
- * but it had still better be PTE-aligned.
- */
- if ( !IS_ALIGNED(addr, sizeof(ol1e)) )
- {
- ASSERT_UNREACHABLE();
- return GNTST_general_error;
- }
-
- gmfn = addr >> PAGE_SHIFT;
- page = get_page_from_gfn(d, gmfn, NULL, P2M_ALLOC);
-
- if ( unlikely(!page) )
- {
- gdprintk(XENLOG_WARNING, "Could not get page for normal update\n");
- return GNTST_general_error;
- }
-
- mfn = mfn_x(page_to_mfn(page));
- va = map_domain_page(_mfn(mfn));
- va = (void *)((unsigned long)va + ((unsigned long)addr & ~PAGE_MASK));
-
- if ( !page_lock(page) )
- {
- rc = GNTST_general_error;
- goto failed;
- }
-
- if ( (page->u.inuse.type_info & PGT_type_mask) != PGT_l1_page_table )
- {
- page_unlock(page);
- rc = GNTST_general_error;
- goto failed;
- }
-
- ol1e = *(l1_pgentry_t *)va;
-
- /*
- * Check that the PTE supplied actually maps frame (with appropriate
- * permissions).
- */
- if ( unlikely(l1e_get_pfn(ol1e) != frame) ||
- unlikely((l1e_get_flags(ol1e) ^ grant_pte_flags) &
- (_PAGE_PRESENT | _PAGE_RW)) )
- {
- page_unlock(page);
- gdprintk(XENLOG_ERR,
- "PTE %"PRIpte" at %"PRIx64" doesn't match grant
(%"PRIpte")\n",
- l1e_get_intpte(ol1e), addr,
- l1e_get_intpte(l1e_from_pfn(frame, grant_pte_flags)));
- rc = GNTST_general_error;
- goto failed;
- }
-
- if ( unlikely((l1e_get_flags(ol1e) ^ grant_pte_flags) &
- ~(_PAGE_AVAIL | PAGE_CACHE_ATTRS)) )
- gdprintk(XENLOG_WARNING,
- "PTE flags %x at %"PRIx64" don't match grant (%x)\n",
- l1e_get_flags(ol1e), addr, grant_pte_flags);
-
- /* Delete pagetable entry. */
- if ( unlikely(!UPDATE_ENTRY(l1,
- (l1_pgentry_t *)va, ol1e, l1e_empty(), mfn,
- d->vcpu[0] /* Change if we go to per-vcpu
shadows. */,
- 0)) )
- {
- page_unlock(page);
- gdprintk(XENLOG_WARNING, "Cannot delete PTE entry at %"PRIx64"\n",
- addr);
- rc = GNTST_general_error;
- goto failed;
- }
-
- page_unlock(page);
-
- failed:
- unmap_domain_page(va);
- put_page(page);
- return rc;
-}
-
-static int replace_grant_va_mapping(
- unsigned long addr, unsigned long frame, unsigned int grant_pte_flags,
- l1_pgentry_t nl1e, struct vcpu *v)
-{
- l1_pgentry_t *pl1e, ol1e;
- mfn_t gl1mfn;
- struct page_info *l1pg;
- int rc = 0;
-
- pl1e = map_guest_l1e(addr, &gl1mfn);
- if ( !pl1e )
- {
- gdprintk(XENLOG_WARNING, "Could not find L1 PTE for address %lx\n",
addr);
- return GNTST_general_error;
- }
-
- if ( !get_page_from_mfn(gl1mfn, current->domain) )
- {
- rc = GNTST_general_error;
- goto out;
- }
-
- l1pg = mfn_to_page(gl1mfn);
- if ( !page_lock(l1pg) )
- {
- rc = GNTST_general_error;
- put_page(l1pg);
- goto out;
- }
-
- if ( (l1pg->u.inuse.type_info & PGT_type_mask) != PGT_l1_page_table )
- {
- rc = GNTST_general_error;
- goto unlock_and_out;
- }
-
- ol1e = *pl1e;
-
- /*
- * Check that the virtual address supplied is actually mapped to frame
- * (with appropriate permissions).
- */
- if ( unlikely(l1e_get_pfn(ol1e) != frame) ||
- unlikely((l1e_get_flags(ol1e) ^ grant_pte_flags) &
- (_PAGE_PRESENT | _PAGE_RW)) )
- {
- gdprintk(XENLOG_ERR,
- "PTE %"PRIpte" for %lx doesn't match grant (%"PRIpte")\n",
- l1e_get_intpte(ol1e), addr,
- l1e_get_intpte(l1e_from_pfn(frame, grant_pte_flags)));
- rc = GNTST_general_error;
- goto unlock_and_out;
- }
-
- if ( unlikely((l1e_get_flags(ol1e) ^ grant_pte_flags) &
- ~(_PAGE_AVAIL | PAGE_CACHE_ATTRS)) )
- gdprintk(XENLOG_WARNING,
- "PTE flags %x for %"PRIx64" don't match grant (%x)\n",
- l1e_get_flags(ol1e), addr, grant_pte_flags);
-
- /* Delete pagetable entry. */
- if ( unlikely(!UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, mfn_x(gl1mfn), v, 0)) )
- {
- gdprintk(XENLOG_WARNING, "Cannot delete PTE entry for %"PRIx64"\n",
- addr);
- rc = GNTST_general_error;
- goto unlock_and_out;
- }
-
- unlock_and_out:
- page_unlock(l1pg);
- put_page(l1pg);
- out:
- unmap_domain_page(pl1e);
- return rc;
-}
-
-static int destroy_grant_va_mapping(
- unsigned long addr, unsigned long frame, unsigned int grant_pte_flags,
- struct vcpu *v)
-{
- return replace_grant_va_mapping(addr, frame, grant_pte_flags,
- l1e_empty(), v);
-}
-
int create_grant_pv_mapping(uint64_t addr, unsigned long frame,
unsigned int flags, unsigned int cache_flags)
{
@@ -4136,12 +3959,14 @@ int replace_grant_pv_mapping(uint64_t addr, unsigned
long frame,
{
struct vcpu *curr = current;
struct domain *currd = curr->domain;
- l1_pgentry_t ol1e;
- int rc;
+ l1_pgentry_t nl1e = l1e_empty(), ol1e, *pl1e;
+ struct page_info *page;
+ mfn_t gl1mfn;
+ int rc = GNTST_general_error;
unsigned int grant_pte_flags = grant_to_pte_flags(flags, 0);
/*
- * On top of the explicit settings done by create_grant_host_mapping()
+ * On top of the explicit settings done by create_pv_host_mapping()
* also open-code relevant parts of adjust_guest_l1e(). Don't mirror
* available and cachability flags, though.
*/
@@ -4150,24 +3975,96 @@ int replace_grant_pv_mapping(uint64_t addr, unsigned
long frame,
? _PAGE_GLOBAL
: _PAGE_GUEST_KERNEL | _PAGE_USER;
+ /*
+ * addr comes from Xen's active_entry tracking, and was used successfully
+ * to create a grant.
+ *
+ * The meaning of addr depends on GNTMAP_contains_pte. It is either a
+ * machine address of an L1e the guest has nominated to be altered, or a
+ * linear address we need to look up the appropriate L1e for.
+ *
+ * Passing a new_addr of zero is taken to mean destroy. Passing a
+ * non-zero new_addr has only ever been available via
+ * GNTABOP_unmap_and_replace and only when using linear addresses.
+ */
if ( flags & GNTMAP_contains_pte )
{
- if ( !new_addr )
- return destroy_grant_pte_mapping(addr, frame, grant_pte_flags,
- currd);
+ /* Replace not available in this addressing mode. */
+ if ( new_addr )
+ goto out;
+
+ if ( !IS_ALIGNED(addr, sizeof(nl1e)) )
+ {
+ ASSERT_UNREACHABLE();
+ goto out;
+ }
+
+ gl1mfn = _mfn(addr >> PAGE_SHIFT);
+
+ if ( !get_page_from_mfn(gl1mfn, currd) )
+ goto out;
+
+ pl1e = map_domain_page(gl1mfn) + (addr & ~PAGE_MASK);
+ }
+ else
+ {
+ if ( new_addr && !steal_linear_address(new_addr, &nl1e) )
+ goto out;
+
+ pl1e = map_guest_l1e(addr, &gl1mfn);
- return GNTST_general_error;
+ if ( !pl1e )
+ goto out;
+
+ if ( !get_page_from_mfn(gl1mfn, currd) )
+ goto out_unmap;
+ }
+
+ page = mfn_to_page(gl1mfn);
+
+ if ( !page_lock(page) )
+ goto out_put;
+
+ if ( (page->u.inuse.type_info & PGT_type_mask) != PGT_l1_page_table )
+ goto out_unlock;
+
+ ol1e = *pl1e;
+
+ /*
+ * Check that the virtual address supplied is actually mapped to frame
+ * (with appropriate permissions).
+ */
+ if ( unlikely(l1e_get_pfn(ol1e) != frame) ||
+ unlikely((l1e_get_flags(ol1e) ^ grant_pte_flags) &
+ (_PAGE_PRESENT | _PAGE_RW)) )
+ {
+ gdprintk(XENLOG_ERR,
+ "PTE %"PRIpte" for %lx doesn't match grant (%"PRIpte")\n",
+ l1e_get_intpte(ol1e), addr,
+ l1e_get_intpte(l1e_from_pfn(frame, grant_pte_flags)));
+ goto out_unlock;
}
- if ( !new_addr )
- return destroy_grant_va_mapping(addr, frame, grant_pte_flags, curr);
+ if ( unlikely((l1e_get_flags(ol1e) ^ grant_pte_flags) &
+ ~(_PAGE_AVAIL | PAGE_CACHE_ATTRS)) )
+ gdprintk(XENLOG_WARNING,
+ "PTE flags %x for %"PRIx64" don't match grant (%x)\n",
+ l1e_get_flags(ol1e), addr, grant_pte_flags);
- if ( !steal_linear_address(new_addr, &ol1e) )
- return GNTST_general_error;
+ if ( UPDATE_ENTRY(l1, pl1e, ol1e, nl1e, mfn_x(gl1mfn), curr, 0) )
+ rc = GNTST_okay;
- rc = replace_grant_va_mapping(addr, frame, grant_pte_flags, ol1e, curr);
+ out_unlock:
+ page_unlock(page);
+ out_put:
+ put_page(page);
+ out_unmap:
+ unmap_domain_page(pl1e);
+
+ out:
+ /* If there was an error, we are still responsible for the stolen pte. */
if ( rc )
- put_page_from_l1e(ol1e, currd);
+ put_page_from_l1e(nl1e, currd);
return rc;
}
--
2.1.4
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