# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1233760126 0
# Node ID 13a0272c8c024fca83bc991c7e2da992d07bc8eb
# Parent 271697e6d9b2b85ce348548f99166be450d1cf5a
x86: Clean up PV guest LDT handling.
1. Do not touch deferred_ops in invalidate_shadow_ldt(), as we may
not always be in a context where deferred_ops is valid.
2. Protected the shadow LDT with a lock, now that mmu updates are not
protected by the per-domain lock.
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
xen/arch/x86/domain.c | 2 ++
xen/arch/x86/mm.c | 40 +++++++++++++++++++++++-----------------
xen/include/asm-x86/domain.h | 1 +
3 files changed, 26 insertions(+), 17 deletions(-)
diff -r 271697e6d9b2 -r 13a0272c8c02 xen/arch/x86/domain.c
--- a/xen/arch/x86/domain.c Wed Feb 04 14:46:47 2009 +0000
+++ b/xen/arch/x86/domain.c Wed Feb 04 15:08:46 2009 +0000
@@ -352,6 +352,8 @@ int vcpu_initialise(struct vcpu *v)
v->arch.perdomain_ptes =
d->arch.mm_perdomain_pt + (v->vcpu_id << GDT_LDT_VCPU_SHIFT);
+ spin_lock_init(&v->arch.shadow_ldt_lock);
+
return (is_pv_32on64_vcpu(v) ? setup_compat_l4(v) : 0);
}
diff -r 271697e6d9b2 -r 13a0272c8c02 xen/arch/x86/mm.c
--- a/xen/arch/x86/mm.c Wed Feb 04 14:46:47 2009 +0000
+++ b/xen/arch/x86/mm.c Wed Feb 04 15:08:46 2009 +0000
@@ -179,12 +179,6 @@ l2_pgentry_t *compat_idle_pg_table_l2 =
#define l3_disallow_mask(d) L3_DISALLOW_MASK
#endif
-static void queue_deferred_ops(struct domain *d, unsigned int ops)
-{
- ASSERT(d == current->domain);
- this_cpu(percpu_mm_info).deferred_ops |= ops;
-}
-
void __init init_frametable(void)
{
unsigned long nr_pages, page_step, i, mfn;
@@ -464,14 +458,18 @@ void update_cr3(struct vcpu *v)
}
-static void invalidate_shadow_ldt(struct vcpu *v)
+static void invalidate_shadow_ldt(struct vcpu *v, int flush)
{
int i;
unsigned long pfn;
struct page_info *page;
+ BUG_ON(unlikely(in_irq()));
+
+ spin_lock(&v->arch.shadow_ldt_lock);
+
if ( v->arch.shadow_ldt_mapcnt == 0 )
- return;
+ goto out;
v->arch.shadow_ldt_mapcnt = 0;
@@ -486,11 +484,12 @@ static void invalidate_shadow_ldt(struct
put_page_and_type(page);
}
- /* Dispose of the (now possibly invalid) mappings from the TLB. */
- if ( v == current )
- queue_deferred_ops(v->domain, DOP_FLUSH_TLB | DOP_RELOAD_LDT);
- else
- flush_tlb_mask(v->domain->domain_dirty_cpumask);
+ /* Rid TLBs of stale mappings (guest mappings and shadow mappings). */
+ if ( flush )
+ flush_tlb_mask(v->vcpu_dirty_cpumask);
+
+ out:
+ spin_unlock(&v->arch.shadow_ldt_lock);
}
@@ -541,8 +540,10 @@ int map_ldt_shadow_page(unsigned int off
nl1e = l1e_from_pfn(mfn, l1e_get_flags(l1e) | _PAGE_RW);
+ spin_lock(&v->arch.shadow_ldt_lock);
l1e_write(&v->arch.perdomain_ptes[off + 16], nl1e);
v->arch.shadow_ldt_mapcnt++;
+ spin_unlock(&v->arch.shadow_ldt_lock);
return 1;
}
@@ -989,7 +990,7 @@ void put_page_from_l1e(l1_pgentry_t l1e,
(d == e) )
{
for_each_vcpu ( d, v )
- invalidate_shadow_ldt(v);
+ invalidate_shadow_ldt(v, 1);
}
put_page(page);
}
@@ -2375,7 +2376,7 @@ int new_guest_cr3(unsigned long mfn)
return 0;
}
- invalidate_shadow_ldt(curr);
+ invalidate_shadow_ldt(curr, 0);
write_ptbase(curr);
return 1;
@@ -2390,7 +2391,7 @@ int new_guest_cr3(unsigned long mfn)
return 0;
}
- invalidate_shadow_ldt(curr);
+ invalidate_shadow_ldt(curr, 0);
old_base_mfn = pagetable_get_pfn(curr->arch.guest_table);
@@ -2427,6 +2428,10 @@ static void process_deferred_ops(void)
flush_tlb_local();
}
+ /*
+ * Do this after flushing TLBs, to ensure we see fresh LDT mappings
+ * via the linear pagetable mapping.
+ */
if ( deferred_ops & DOP_RELOAD_LDT )
(void)map_ldt_shadow_page(0);
@@ -2799,7 +2804,8 @@ int do_mmuext_op(
else if ( (curr->arch.guest_context.ldt_ents != ents) ||
(curr->arch.guest_context.ldt_base != ptr) )
{
- invalidate_shadow_ldt(curr);
+ invalidate_shadow_ldt(curr, 0);
+ this_cpu(percpu_mm_info).deferred_ops |= DOP_FLUSH_TLB;
curr->arch.guest_context.ldt_base = ptr;
curr->arch.guest_context.ldt_ents = ents;
load_LDT(curr);
diff -r 271697e6d9b2 -r 13a0272c8c02 xen/include/asm-x86/domain.h
--- a/xen/include/asm-x86/domain.h Wed Feb 04 14:46:47 2009 +0000
+++ b/xen/include/asm-x86/domain.h Wed Feb 04 15:08:46 2009 +0000
@@ -352,6 +352,7 @@ struct arch_vcpu
/* Current LDT details. */
unsigned long shadow_ldt_mapcnt;
+ spinlock_t shadow_ldt_lock;
struct paging_vcpu paging;
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