xen-project/xen
1
0 Fork 1
mirror of https://github.com/xen-project/xen.git synced 2026-10-28 10:11:27 +01:00
Code Issues Activity

IOMMU/x86: perform PV Dom0 mappings in batches

Browse Source 
For large page mappings to be easily usable (i.e. in particular without
un-shattering of smaller page mappings) and for mapping operations to
then also be more efficient, pass batches of Dom0 memory to iommu_map().
In dom0_construct_pv() and its helpers (covering strict mode) this
additionally requires establishing the type of those pages (albeit with
zero type references).

The earlier establishing of PGT_writable_page | PGT_validated requires
the existing places where this gets done (through get_page_and_type())
to be updated: For pages which actually have a mapping, the type
refcount needs to be 1.

There is actually a related bug that gets fixed here as a side effect:
Typically the last L1 table would get marked as such only after
get_page_and_type(..., PGT_writable_page). While this is fine as far as
refcounting goes, the page did remain mapped in the IOMMU in this case
(when "iommu=dom0-strict").

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Paul Durrant <paul@xen.org>
This commit is contained in:
Jan Beulich committed 2022-07-25 15:32:59 +02:00
1 parent c519819ff5
commit c1e1564c89
2 files changed
+129 -20
Download Patch File Download Diff File Expand all files Collapse all files

No files matched your search

xen/arch/x86/pv/dom0_build.c
+90 -7
View File
@@ -46,7 +46,8 @@ void __init dom0_update_physmap(bool compat, unsigned long pfn,
static __init void mark_pv_pt_pages_rdonly(struct domain *d,
l4_pgentry_t *l4start,
unsigned long vpt_start,
unsigned long nr_pt_pages)
unsigned long nr_pt_pages,
unsigned int *flush_flags)
{
unsigned long count;
struct page_info *page;
@@ -71,6 +72,14 @@ static __init void mark_pv_pt_pages_rdonly(struct domain *d,
ASSERT((page->u.inuse.type_info & PGT_type_mask) <= PGT_root_page_table);
ASSERT(!(page->u.inuse.type_info & ~(PGT_type_mask | PGT_pae_xen_l2)));
/*
* Page table pages need to be removed from the IOMMU again in case
* iommu_memory_setup() ended up mapping them.
*/
if ( need_iommu_pt_sync(d) &&
iommu_unmap(d, _dfn(mfn_x(page_to_mfn(page))), 1, 0, flush_flags) )
BUG();
/* Read-only mapping + PGC_allocated + page-table page. */
page->count_info = PGC_allocated | 3;
page->u.inuse.type_info |= PGT_validated | 1;
@@ -107,11 +116,56 @@ static __init void mark_pv_pt_pages_rdonly(struct domain *d,
unmap_domain_page(pl3e);
}
static void __init iommu_memory_setup(struct domain *d, const char *what,
struct page_info *page, unsigned long nr,
unsigned int *flush_flags)
{
long rc;
mfn_t mfn = page_to_mfn(page);
if ( !need_iommu_pt_sync(d) )
return;
while ( (rc = iommu_map(d, _dfn(mfn_x(mfn)), mfn, nr,
IOMMUF_readable | IOMMUF_writable | IOMMUF_preempt,
flush_flags)) > 0 )
{
mfn_add(mfn, rc);
nr -= rc;
/* See comment below. */
for ( ; rc--; ++page )
{
ASSERT(!page->u.inuse.type_info);
page->u.inuse.type_info = PGT_writable_page | PGT_validated;
}
process_pending_softirqs();
}
if ( rc )
{
printk(XENLOG_ERR
"pre-mapping %s MFN [%lx,%lx) into IOMMU failed: %ld\n",
what, mfn_x(mfn), mfn_x(mfn) + nr, rc);
return;
}
/*
* For successfully established IOMMU mappings the type of the page(s)
* needs to match (for _get_page_type() to unmap upon type change). Set
* the page(s) to writable with no type ref.
*/
for ( ; nr--; ++page )
{
ASSERT(!page->u.inuse.type_info);
page->u.inuse.type_info = PGT_writable_page | PGT_validated;
}
}
static __init void setup_pv_physmap(struct domain *d, unsigned long pgtbl_pfn,
unsigned long v_start, unsigned long v_end,
unsigned long vphysmap_start,
unsigned long vphysmap_end,
unsigned long nr_pages)
unsigned long nr_pages,
unsigned int *flush_flags)
{
struct page_info *page = NULL;
l4_pgentry_t *pl4e, *l4start = map_domain_page(_mfn(pgtbl_pfn));
@@ -177,6 +231,10 @@ static __init void setup_pv_physmap(struct domain *d, unsigned long pgtbl_pfn,
L3_PAGETABLE_SHIFT - PAGE_SHIFT,
MEMF_no_scrub)) != NULL )
{
iommu_memory_setup(d, "P2M 1G", page,
SUPERPAGE_PAGES * SUPERPAGE_PAGES,
flush_flags);
*pl3e = l3e_from_page(page, L1_PROT|_PAGE_DIRTY|_PAGE_PSE);
vphysmap_start += 1UL << L3_PAGETABLE_SHIFT;
continue;
@@ -203,6 +261,9 @@ static __init void setup_pv_physmap(struct domain *d, unsigned long pgtbl_pfn,
L2_PAGETABLE_SHIFT - PAGE_SHIFT,
MEMF_no_scrub)) != NULL )
{
iommu_memory_setup(d, "P2M 2M", page, SUPERPAGE_PAGES,
flush_flags);
*pl2e = l2e_from_page(page, L1_PROT|_PAGE_DIRTY|_PAGE_PSE);
vphysmap_start += 1UL << L2_PAGETABLE_SHIFT;
continue;
@@ -311,6 +372,7 @@ int __init dom0_construct_pv(struct domain *d,
unsigned long initrd_pfn = -1, initrd_mfn = 0;
unsigned long count;
struct page_info *page = NULL;
unsigned int flush_flags = 0;
start_info_t *si;
struct vcpu *v = d->vcpu[0];
void *image_base = bootstrap_map(image);
@@ -573,6 +635,9 @@ int __init dom0_construct_pv(struct domain *d,
BUG();
}
initrd->mod_end = 0;
iommu_memory_setup(d, "initrd", mfn_to_page(_mfn(initrd_mfn)),
PFN_UP(initrd_len), &flush_flags);
}
printk("PHYSICAL MEMORY ARRANGEMENT:\n"
@@ -606,6 +671,13 @@ int __init dom0_construct_pv(struct domain *d,
process_pending_softirqs();
/*
* Map the full range here and then punch holes for page tables
* alongside marking them as such in mark_pv_pt_pages_rdonly().
*/
iommu_memory_setup(d, "init-alloc", mfn_to_page(_mfn(alloc_spfn)),
alloc_epfn - alloc_spfn, &flush_flags);
mpt_alloc = (vpt_start - v_start) + pfn_to_paddr(alloc_spfn);
if ( vinitrd_start )
mpt_alloc -= PAGE_ALIGN(initrd_len);
@@ -690,7 +762,8 @@ int __init dom0_construct_pv(struct domain *d,
l1tab++;
page = mfn_to_page(_mfn(mfn));
if ( !page->u.inuse.type_info &&
if ( (!page->u.inuse.type_info ||
page->u.inuse.type_info == (PGT_writable_page | PGT_validated)) &&
!get_page_and_type(page, d, PGT_writable_page) )
BUG();
}
@@ -719,7 +792,7 @@ int __init dom0_construct_pv(struct domain *d,
}
/* Pages that are part of page tables must be read only. */
mark_pv_pt_pages_rdonly(d, l4start, vpt_start, nr_pt_pages);
mark_pv_pt_pages_rdonly(d, l4start, vpt_start, nr_pt_pages, &flush_flags);
/* Mask all upcalls... */
for ( i = 0; i < XEN_LEGACY_MAX_VCPUS; i++ )
@@ -794,7 +867,7 @@ int __init dom0_construct_pv(struct domain *d,
{
pfn = pagetable_get_pfn(v->arch.guest_table);
setup_pv_physmap(d, pfn, v_start, v_end, vphysmap_start, vphysmap_end,
nr_pages);
nr_pages, &flush_flags);
}
/* Write the phys->machine and machine->phys table entries. */
@@ -825,7 +898,9 @@ int __init dom0_construct_pv(struct domain *d,
if ( get_gpfn_from_mfn(mfn) >= count )
{
BUG_ON(compat);
if ( !page->u.inuse.type_info &&
if ( (!page->u.inuse.type_info ||
page->u.inuse.type_info == (PGT_writable_page |
PGT_validated)) &&
!get_page_and_type(page, d, PGT_writable_page) )
BUG();
@@ -841,8 +916,12 @@ int __init dom0_construct_pv(struct domain *d,
#endif
while ( pfn < nr_pages )
{
if ( (page = alloc_chunk(d, nr_pages - domain_tot_pages(d))) == NULL )
count = domain_tot_pages(d);
if ( (page = alloc_chunk(d, nr_pages - count)) == NULL )
panic("Not enough RAM for DOM0 reservation\n");
iommu_memory_setup(d, "chunk", page, domain_tot_pages(d) - count,
&flush_flags);
while ( pfn < domain_tot_pages(d) )
{
mfn = mfn_x(page_to_mfn(page));
@@ -857,6 +936,10 @@ int __init dom0_construct_pv(struct domain *d,
}
}
/* Use while() to avoid compiler warning. */
while ( iommu_iotlb_flush_all(d, flush_flags) )
break;
if ( initrd_len != 0 )
{
si->mod_start = vinitrd_start ?: initrd_pfn;
xen/drivers/passthrough/x86/iommu.c
+39 -13
View File
@@ -348,8 +348,8 @@ static unsigned int __hwdom_init hwdom_iommu_map(const struct domain *d,
void __hwdom_init arch_iommu_hwdom_init(struct domain *d)
{
unsigned long i, top, max_pfn;
unsigned int flush_flags = 0;
unsigned long i, top, max_pfn, start, count;
unsigned int flush_flags = 0, start_perms = 0;
BUG_ON(!is_hardware_domain(d));
@@ -380,31 +380,57 @@ void __hwdom_init arch_iommu_hwdom_init(struct domain *d)
* First Mb will get mapped in one go by pvh_populate_p2m(). Avoid
* setting up potentially conflicting mappings here.
*/
i = paging_mode_translate(d) ? PFN_DOWN(MB(1)) : 0;
start = paging_mode_translate(d) ? PFN_DOWN(MB(1)) : 0;
for ( ; i < top; i++ )
for ( i = start, count = 0; i < top; )
{
unsigned long pfn = pdx_to_pfn(i);
unsigned int perms = hwdom_iommu_map(d, pfn, max_pfn);
int rc;
if ( !perms )
rc = 0;
/* nothing */;
else if ( paging_mode_translate(d) )
{
int rc;
rc = p2m_add_identity_entry(d, pfn,
perms & IOMMUF_writable ? p2m_access_rw
: p2m_access_r,
0);
if ( rc )
printk(XENLOG_WARNING
"%pd: identity mapping of %lx failed: %d\n",
d, pfn, rc);
}
else if ( pfn != start + count || perms != start_perms )
{
long rc;
commit:
while ( (rc = iommu_map(d, _dfn(start), _mfn(start), count,
start_perms | IOMMUF_preempt,
&flush_flags)) > 0 )
{
start += rc;
count -= rc;
process_pending_softirqs();
}
if ( rc )
printk(XENLOG_WARNING
"%pd: IOMMU identity mapping of [%lx,%lx) failed: %ld\n",
d, start, start + count, rc);
start = pfn;
count = 1;
start_perms = perms;
}
else
rc = iommu_map(d, _dfn(pfn), _mfn(pfn), 1ul << PAGE_ORDER_4K,
perms, &flush_flags);
++count;
if ( rc )
printk(XENLOG_WARNING "%pd: identity %smapping of %lx failed: %d\n",
d, !paging_mode_translate(d) ? "IOMMU " : "", pfn, rc);
if (!(i & 0xfffff))
if ( !(++i & 0xfffff) )
process_pending_softirqs();
if ( i == top && count )
goto commit;
}
/* Use if to avoid compiler warning */
Reference in new issue
xen-project/xen
Block a user
Blocking a user prevents them from interacting with repositories, such as opening or commenting on pull requests or issues. Learn more about blocking a user.

The note is not visible to the blocked user.