# HG changeset patch
# User kfraser@xxxxxxxxxxxxxxxxxxxxx
# Date 1176463746 -3600
# Node ID ba8d4bc2435a742f74909c3fc9efab1655aae41f
# Parent 0b14423e75f8e5207c87b0d5de1a40dcf7713002
hvm: Xen must take care to hold a reference to ioreq pages, to ensure
that domain runs only when it has valid mapped ioreq pages, and to
safely drop ioreq page references when a domain dies.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
---
xen/arch/x86/domain.c | 4 +
xen/arch/x86/hvm/hvm.c | 106 ++++++++++++++++++++++++++------------
xen/arch/x86/x86_32/domain_page.c | 21 +++++++
xen/common/domain.c | 2
xen/include/asm-x86/hvm/hvm.h | 1
xen/include/xen/domain_page.h | 13 +++-
6 files changed, 111 insertions(+), 36 deletions(-)
diff -r 0b14423e75f8 -r ba8d4bc2435a xen/arch/x86/domain.c
--- a/xen/arch/x86/domain.c Fri Apr 13 12:01:37 2007 +0100
+++ b/xen/arch/x86/domain.c Fri Apr 13 12:29:06 2007 +0100
@@ -1540,8 +1540,10 @@ void domain_relinquish_resources(struct
relinquish_memory(d, &d->xenpage_list, PGT_l2_page_table);
relinquish_memory(d, &d->page_list, PGT_l2_page_table);
- /* Free page used by xen oprofile buffer */
+ /* Free page used by xen oprofile buffer. */
free_xenoprof_pages(d);
+
+ hvm_domain_relinquish_resources(d);
}
void arch_dump_domain_info(struct domain *d)
diff -r 0b14423e75f8 -r ba8d4bc2435a xen/arch/x86/hvm/hvm.c
--- a/xen/arch/x86/hvm/hvm.c Fri Apr 13 12:01:37 2007 +0100
+++ b/xen/arch/x86/hvm/hvm.c Fri Apr 13 12:29:06 2007 +0100
@@ -146,6 +146,59 @@ void hvm_do_resume(struct vcpu *v)
}
}
+static void hvm_clear_ioreq_pfn(
+ struct domain *d, unsigned long *pva)
+{
+ unsigned long va, mfn;
+
+ BUG_ON(!d->is_dying);
+
+ if ( (va = xchg(pva, 0UL)) == 0UL )
+ return;
+
+ mfn = mfn_from_mapped_domain_page((void *)va);
+ unmap_domain_page_global((void *)va);
+ put_page_and_type(mfn_to_page(mfn));
+}
+
+static int hvm_set_ioreq_pfn(
+ struct domain *d, unsigned long *pva, unsigned long gmfn)
+{
+ unsigned long mfn;
+ void *va;
+
+ mfn = gmfn_to_mfn(d, gmfn);
+ if ( !mfn_valid(mfn) ||
+ !get_page_and_type(mfn_to_page(mfn), d, PGT_writable_page) )
+ return -EINVAL;
+
+ va = map_domain_page_global(mfn);
+ if ( va == NULL )
+ {
+ put_page_and_type(mfn_to_page(mfn));
+ return -ENOMEM;
+ }
+
+ if ( cmpxchg(pva, 0UL, (unsigned long)va) != 0UL )
+ {
+ unmap_domain_page_global(va);
+ put_page_and_type(mfn_to_page(mfn));
+ return -EINVAL;
+ }
+
+ /*
+ * Check dying status /after/ setting *pva. cmpxchg() is a barrier.
+ * We race against hvm_domain_relinquish_resources().
+ */
+ if ( d->is_dying )
+ hvm_clear_ioreq_pfn(d, pva);
+
+ /* Balance the domain_pause() in hvm_domain_initialise(). */
+ domain_unpause(d);
+
+ return 0;
+}
+
int hvm_domain_initialise(struct domain *d)
{
int rc;
@@ -161,7 +214,6 @@ int hvm_domain_initialise(struct domain
spin_lock_init(&d->arch.hvm_domain.buffered_io_lock);
spin_lock_init(&d->arch.hvm_domain.irq_lock);
- /* paging support will be determined inside paging.c */
rc = paging_enable(d, PG_refcounts|PG_translate|PG_external);
if ( rc != 0 )
return rc;
@@ -169,7 +221,17 @@ int hvm_domain_initialise(struct domain
vpic_init(d);
vioapic_init(d);
+ /* Do not allow domain to run until it has ioreq shared pages. */
+ domain_pause(d); /* HVM_PARAM_IOREQ_PFN */
+ domain_pause(d); /* HVM_PARAM_BUFIOREQ_PFN */
+
return 0;
+}
+
+void hvm_domain_relinquish_resources(struct domain *d)
+{
+ hvm_clear_ioreq_pfn(d, &d->arch.hvm_domain.shared_page_va);
+ hvm_clear_ioreq_pfn(d, &d->arch.hvm_domain.buffered_io_va);
}
void hvm_domain_destroy(struct domain *d)
@@ -178,13 +240,6 @@ void hvm_domain_destroy(struct domain *d
rtc_deinit(d);
pmtimer_deinit(d);
hpet_deinit(d);
-
- if ( d->arch.hvm_domain.shared_page_va )
- unmap_domain_page_global(
- (void *)d->arch.hvm_domain.shared_page_va);
-
- if ( d->arch.hvm_domain.buffered_io_va )
- unmap_domain_page_global((void *)d->arch.hvm_domain.buffered_io_va);
}
static int hvm_save_cpu_ctxt(struct domain *d, hvm_domain_context_t *h)
@@ -928,8 +983,6 @@ long do_hvm_op(unsigned long op, XEN_GUE
struct xen_hvm_param a;
struct domain *d;
struct vcpu *v;
- unsigned long mfn;
- void *p;
if ( copy_from_guest(&a, arg, 1) )
return -EFAULT;
@@ -956,30 +1009,19 @@ long do_hvm_op(unsigned long op, XEN_GUE
switch ( a.index )
{
case HVM_PARAM_IOREQ_PFN:
- if ( d->arch.hvm_domain.shared_page_va )
- goto param_fail;
- mfn = gmfn_to_mfn(d, a.value);
- if ( mfn == INVALID_MFN )
- goto param_fail;
- p = map_domain_page_global(mfn);
- if ( p == NULL )
- goto param_fail;
- d->arch.hvm_domain.shared_page_va = (unsigned long)p;
- /* Initialise evtchn port info if VCPUs already created. */
- for_each_vcpu ( d, v )
- get_vio(d, v->vcpu_id)->vp_eport =
- v->arch.hvm_vcpu.xen_port;
+ rc = hvm_set_ioreq_pfn(
+ d, &d->arch.hvm_domain.shared_page_va, a.value);
+ if ( rc == 0 )
+ {
+ /* Initialise evtchn port info if VCPUs already created. */
+ for_each_vcpu ( d, v )
+ get_vio(d, v->vcpu_id)->vp_eport =
+ v->arch.hvm_vcpu.xen_port;
+ }
break;
case HVM_PARAM_BUFIOREQ_PFN:
- if ( d->arch.hvm_domain.buffered_io_va )
- goto param_fail;
- mfn = gmfn_to_mfn(d, a.value);
- if ( mfn == INVALID_MFN )
- goto param_fail;
- p = map_domain_page_global(mfn);
- if ( p == NULL )
- goto param_fail;
- d->arch.hvm_domain.buffered_io_va = (unsigned long)p;
+ rc = hvm_set_ioreq_pfn(
+ d, &d->arch.hvm_domain.buffered_io_va, a.value);
break;
case HVM_PARAM_CALLBACK_IRQ:
hvm_set_callback_via(d, a.value);
diff -r 0b14423e75f8 -r ba8d4bc2435a xen/arch/x86/x86_32/domain_page.c
--- a/xen/arch/x86/x86_32/domain_page.c Fri Apr 13 12:01:37 2007 +0100
+++ b/xen/arch/x86/x86_32/domain_page.c Fri Apr 13 12:29:06 2007 +0100
@@ -251,3 +251,24 @@ void unmap_domain_page_global(void *va)
idx = (__va - IOREMAP_VIRT_START) >> PAGE_SHIFT;
set_bit(idx, garbage);
}
+
+unsigned long mfn_from_mapped_domain_page(void *va)
+{
+ unsigned long __va = (unsigned long)va;
+ l2_pgentry_t *pl2e;
+ l1_pgentry_t *pl1e;
+ unsigned int idx;
+ struct mapcache *cache;
+
+ if ( (__va >= MAPCACHE_VIRT_START) && (__va < MAPCACHE_VIRT_END) )
+ {
+ cache = &mapcache_current_vcpu()->domain->arch.mapcache;
+ idx = ((unsigned long)va - MAPCACHE_VIRT_START) >> PAGE_SHIFT;
+ return l1e_get_pfn(cache->l1tab[idx]);
+ }
+
+ ASSERT(__va >= IOREMAP_VIRT_START);
+ pl2e = virt_to_xen_l2e(__va);
+ pl1e = l2e_to_l1e(*pl2e) + l1_table_offset(__va);
+ return l1e_get_pfn(*pl1e);
+}
diff -r 0b14423e75f8 -r ba8d4bc2435a xen/common/domain.c
--- a/xen/common/domain.c Fri Apr 13 12:01:37 2007 +0100
+++ b/xen/common/domain.c Fri Apr 13 12:29:06 2007 +0100
@@ -314,7 +314,7 @@ void domain_kill(struct domain *d)
}
/* Tear down state /after/ setting the dying flag. */
- smp_wmb();
+ smp_mb();
gnttab_release_mappings(d);
domain_relinquish_resources(d);
diff -r 0b14423e75f8 -r ba8d4bc2435a xen/include/asm-x86/hvm/hvm.h
--- a/xen/include/asm-x86/hvm/hvm.h Fri Apr 13 12:01:37 2007 +0100
+++ b/xen/include/asm-x86/hvm/hvm.h Fri Apr 13 12:29:06 2007 +0100
@@ -145,6 +145,7 @@ extern struct hvm_function_table hvm_fun
extern struct hvm_function_table hvm_funcs;
int hvm_domain_initialise(struct domain *d);
+void hvm_domain_relinquish_resources(struct domain *d);
void hvm_domain_destroy(struct domain *d);
int hvm_vcpu_initialise(struct vcpu *v);
diff -r 0b14423e75f8 -r ba8d4bc2435a xen/include/xen/domain_page.h
--- a/xen/include/xen/domain_page.h Fri Apr 13 12:01:37 2007 +0100
+++ b/xen/include/xen/domain_page.h Fri Apr 13 12:29:06 2007 +0100
@@ -33,6 +33,13 @@ void unmap_domain_page(void *va);
*/
void *map_domain_page_global(unsigned long mfn);
void unmap_domain_page_global(void *va);
+
+/*
+ * Convert a VA (within a page previously mapped in the context of the
+ * currently-executing VCPU via a call to map_domain_page(), or via a
+ * previous call to map_domain_page_global()) to the mapped page frame.
+ */
+unsigned long mfn_from_mapped_domain_page(void *va);
#define DMCACHE_ENTRY_VALID 1U
#define DMCACHE_ENTRY_HELD 2U
@@ -96,11 +103,13 @@ domain_mmap_cache_destroy(struct domain_
#else /* !CONFIG_DOMAIN_PAGE */
-#define map_domain_page(mfn) maddr_to_virt((mfn)<<PAGE_SHIFT)
+#define map_domain_page(mfn) mfn_to_virt(mfn)
#define unmap_domain_page(va) ((void)(va))
-#define map_domain_page_global(mfn) maddr_to_virt((mfn)<<PAGE_SHIFT)
+#define map_domain_page_global(mfn) mfn_to_virt(mfn)
#define unmap_domain_page_global(va) ((void)(va))
+
+#define mfn_from_mapped_domain_page(va) virt_to_mfn(va)
struct domain_mmap_cache {
};
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