# HG changeset patch
# User Tim Deegan <Tim.Deegan@xxxxxxxxxx>
# Date 1309426014 -3600
# Node ID 922e0beae95b436c1474b88847e13775a6053cf9
# Parent 80e00ac43548717deedca484d483ebc41b78d076
x86/p2m: Add p2m_change_type_range() operation
that defers the nested-p2m flush until the entire batch has been updated.
Use it in the HAP log-dirty operations for tracking VRAM changes.
This should avoid a lot of unpleasant IPI storms as the log-dirty code
on one CPU repeatedly shoots down the nested p2m of another CPU.
Signed-off-by: Tim Deegan <Tim.Deegan@xxxxxxxxxx>
---
diff -r 80e00ac43548 -r 922e0beae95b xen/arch/x86/mm/hap/hap.c
--- a/xen/arch/x86/mm/hap/hap.c Thu Jun 30 10:26:54 2011 +0100
+++ b/xen/arch/x86/mm/hap/hap.c Thu Jun 30 10:26:54 2011 +0100
@@ -58,7 +58,6 @@
static int hap_enable_vram_tracking(struct domain *d)
{
- int i;
struct sh_dirty_vram *dirty_vram = d->arch.hvm_domain.dirty_vram;
if ( !dirty_vram )
@@ -70,8 +69,8 @@
paging_unlock(d);
/* set l1e entries of P2M table to be read-only. */
- for (i = dirty_vram->begin_pfn; i < dirty_vram->end_pfn; i++)
- p2m_change_type(d, i, p2m_ram_rw, p2m_ram_logdirty);
+ p2m_change_type_range(d, dirty_vram->begin_pfn, dirty_vram->end_pfn,
+ p2m_ram_rw, p2m_ram_logdirty);
flush_tlb_mask(d->domain_dirty_cpumask);
return 0;
@@ -79,7 +78,6 @@
static int hap_disable_vram_tracking(struct domain *d)
{
- int i;
struct sh_dirty_vram *dirty_vram = d->arch.hvm_domain.dirty_vram;
if ( !dirty_vram )
@@ -90,8 +88,8 @@
paging_unlock(d);
/* set l1e entries of P2M table with normal mode */
- for (i = dirty_vram->begin_pfn; i < dirty_vram->end_pfn; i++)
- p2m_change_type(d, i, p2m_ram_logdirty, p2m_ram_rw);
+ p2m_change_type_range(d, dirty_vram->begin_pfn, dirty_vram->end_pfn,
+ p2m_ram_logdirty, p2m_ram_rw);
flush_tlb_mask(d->domain_dirty_cpumask);
return 0;
@@ -99,15 +97,14 @@
static void hap_clean_vram_tracking(struct domain *d)
{
- int i;
struct sh_dirty_vram *dirty_vram = d->arch.hvm_domain.dirty_vram;
if ( !dirty_vram )
return;
/* set l1e entries of P2M table to be read-only. */
- for (i = dirty_vram->begin_pfn; i < dirty_vram->end_pfn; i++)
- p2m_change_type(d, i, p2m_ram_rw, p2m_ram_logdirty);
+ p2m_change_type_range(d, dirty_vram->begin_pfn, dirty_vram->end_pfn,
+ p2m_ram_rw, p2m_ram_logdirty);
flush_tlb_mask(d->domain_dirty_cpumask);
}
@@ -863,7 +860,8 @@
paging_lock(d);
old_flags = l1e_get_flags(*p);
- if ( nestedhvm_enabled(d) && (old_flags & _PAGE_PRESENT) ) {
+ if ( nestedhvm_enabled(d) && (old_flags & _PAGE_PRESENT)
+ && !p2m_get_hostp2m(d)->defer_nested_flush ) {
/* We are replacing a valid entry so we need to flush nested p2ms,
* unless the only change is an increase in access rights. */
mfn_t omfn = _mfn(l1e_get_pfn(*p));
diff -r 80e00ac43548 -r 922e0beae95b xen/arch/x86/mm/p2m.c
--- a/xen/arch/x86/mm/p2m.c Thu Jun 30 10:26:54 2011 +0100
+++ b/xen/arch/x86/mm/p2m.c Thu Jun 30 10:26:54 2011 +0100
@@ -537,6 +537,37 @@
return pt;
}
+/* Modify the p2m type of a range of gfns from ot to nt.
+ * Resets the access permissions. */
+void p2m_change_type_range(struct domain *d,
+ unsigned long start, unsigned long end,
+ p2m_type_t ot, p2m_type_t nt)
+{
+ p2m_type_t pt;
+ unsigned long gfn;
+ mfn_t mfn;
+ struct p2m_domain *p2m = p2m_get_hostp2m(d);
+
+ BUG_ON(p2m_is_grant(ot) || p2m_is_grant(nt));
+
+ p2m_lock(p2m);
+ p2m->defer_nested_flush = 1;
+
+ for ( gfn = start; gfn < end; gfn++ )
+ {
+ mfn = gfn_to_mfn_query(d, gfn, &pt);
+ if ( pt == ot )
+ set_p2m_entry(p2m, gfn, mfn, 0, nt, p2m->default_access);
+ }
+
+ p2m->defer_nested_flush = 0;
+ if ( nestedhvm_enabled(d) )
+ p2m_flush_nestedp2m(d);
+ p2m_unlock(p2m);
+}
+
+
+
int
set_mmio_p2m_entry(struct domain *d, unsigned long gfn, mfn_t mfn)
{
diff -r 80e00ac43548 -r 922e0beae95b xen/include/asm-x86/p2m.h
--- a/xen/include/asm-x86/p2m.h Thu Jun 30 10:26:54 2011 +0100
+++ b/xen/include/asm-x86/p2m.h Thu Jun 30 10:26:54 2011 +0100
@@ -209,6 +209,12 @@
#define CR3_EADDR (~0ULL)
uint64_t cr3;
+ /* Host p2m: when this flag is set, don't flush all the nested-p2m
+ * tables on every host-p2m change. The setter of this flag
+ * is responsible for performing the full flush before releasing the
+ * host p2m's lock. */
+ int defer_nested_flush;
+
/* Pages used to construct the p2m */
struct page_list_head pages;
@@ -408,6 +414,11 @@
void p2m_change_entry_type_global(struct domain *d,
p2m_type_t ot, p2m_type_t nt);
+/* Change types across a range of p2m entries (start ... end-1) */
+void p2m_change_type_range(struct domain *d,
+ unsigned long start, unsigned long end,
+ p2m_type_t ot, p2m_type_t nt);
+
/* Compare-exchange the type of a single p2m entry */
p2m_type_t p2m_change_type(struct domain *d, unsigned long gfn,
p2m_type_t ot, p2m_type_t nt);
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