Add support for modifying the per-CPU page-tables entries of remote CPUs, this
will be required in order to setup the page-tables of CPUs before bringing them
up. A restriction is added so that remote page-tables can only be modified as
long as the remote CPU is not yet online.
Non functional change, as there's no user introduced that modifies remote
page-tables.
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
Can be merged with previous patch?
---
xen/arch/x86/include/asm/mm.h | 15 ++++++++++
xen/arch/x86/mm.c | 55 ++++++++++++++++++++++++++---------
2 files changed, 56 insertions(+), 14 deletions(-)
diff --git a/xen/arch/x86/include/asm/mm.h b/xen/arch/x86/include/asm/mm.h
index 34407fb0af06..f883468b1a7c 100644
--- a/xen/arch/x86/include/asm/mm.h
+++ b/xen/arch/x86/include/asm/mm.h
@@ -637,4 +637,19 @@ void setup_perdomain_slot(const struct vcpu *v, root_pgentry_t *root_pgt);
int allocate_perdomain_local_l3(unsigned int cpu);
void free_perdomain_local_l3(unsigned int cpu);
+/* Specify the CPU idle root page-table to use for modifications. */
+int map_pages_to_xen_cpu(
+ unsigned long virt,
+ mfn_t mfn,
+ unsigned long nr_mfns,
+ unsigned int flags,
+ unsigned int cpu);
+int modify_xen_mappings_cpu(unsigned long s, unsigned long e, unsigned int nf,
+ unsigned int cpu);
+static inline int destroy_xen_mappings_cpu(unsigned long s, unsigned long e,
+ unsigned int cpu)
+{
+ return modify_xen_mappings_cpu(s, e, _PAGE_NONE, cpu);
+}
+
#endif /* __ASM_X86_MM_H__ */
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index c468b46a9d1b..faf2d42745d1 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -5021,9 +5021,8 @@ static DEFINE_SPINLOCK(map_pgdir_lock);
* For virt_to_xen_lXe() functions, they take a linear address and return a
* pointer to Xen's LX entry. Caller needs to unmap the pointer.
*/
-static l3_pgentry_t *virt_to_xen_l3e(unsigned long v)
+static l3_pgentry_t *virt_to_xen_l3e_cpu(unsigned long v, unsigned int cpu)
{
- unsigned int cpu = smp_processor_id();
/* Called before idle_vcpu is populated, fallback to idle_pg_table. */
root_pgentry_t *root_pgt = idle_vcpu[cpu] ?
maddr_to_virt(idle_vcpu[cpu]->arch.cr3) : idle_pg_table;
@@ -5062,11 +5061,16 @@ static l3_pgentry_t *virt_to_xen_l3e(unsigned long v)
return map_l3t_from_l4e(*pl4e) + l3_table_offset(v);
}
-static l2_pgentry_t *virt_to_xen_l2e(unsigned long v)
+static l3_pgentry_t *virt_to_xen_l3e(unsigned long v)
+{
+ return virt_to_xen_l3e_cpu(v, smp_processor_id());
+}
+
+static l2_pgentry_t *virt_to_xen_l2e_cpu(unsigned long v, unsigned int cpu)
{
l3_pgentry_t *pl3e, l3e;
- pl3e = virt_to_xen_l3e(v);
+ pl3e = virt_to_xen_l3e_cpu(v, cpu);
if ( !pl3e )
return NULL;
@@ -5100,11 +5104,11 @@ static l2_pgentry_t *virt_to_xen_l2e(unsigned long v)
return map_l2t_from_l3e(l3e) + l2_table_offset(v);
}
-static l1_pgentry_t *virt_to_xen_l1e(unsigned long v)
+static l1_pgentry_t *virt_to_xen_l1e_cpu(unsigned long v, unsigned int cpu)
{
l2_pgentry_t *pl2e, l2e;
- pl2e = virt_to_xen_l2e(v);
+ pl2e = virt_to_xen_l2e_cpu(v, cpu);
if ( !pl2e )
return NULL;
@@ -5220,17 +5224,18 @@ mfn_t xen_map_to_mfn(unsigned long va)
return ret;
}
-int map_pages_to_xen(
+int map_pages_to_xen_cpu(
unsigned long virt,
mfn_t mfn,
unsigned long nr_mfns,
- unsigned int flags)
+ unsigned int flags,
+ unsigned int cpu)
{
bool global = virt < PERCPU_VIRT_START ||
virt >= PERCPU_VIRT_SLOT(PERCPU_SLOTS);
bool locking = system_state > SYS_STATE_boot && global;
const cpumask_t *flush_mask = global ? &cpu_online_map
- : cpumask_of(smp_processor_id());
+ : cpumask_of(cpu);
l3_pgentry_t *pl3e = NULL, ol3e;
l2_pgentry_t *pl2e = NULL, ol2e;
l1_pgentry_t *pl1e, ol1e;
@@ -5257,6 +5262,9 @@ int map_pages_to_xen(
(virt + nr_mfns * PAGE_SIZE >= PERCPU_VIRT_START &&
virt + nr_mfns * PAGE_SIZE < PERCPU_VIRT_SLOT(PERCPU_SLOTS)));
+ /* Only allow modifying remote page-tables if the CPU is not online. */
+ ASSERT(cpu == smp_processor_id() || !cpu_online(cpu));
+
L3T_INIT(current_l3page);
while ( nr_mfns != 0 )
@@ -5266,7 +5274,7 @@ int map_pages_to_xen(
UNMAP_DOMAIN_PAGE(pl3e);
UNMAP_DOMAIN_PAGE(pl2e);
- pl3e = virt_to_xen_l3e(virt);
+ pl3e = virt_to_xen_l3e_cpu(virt, cpu);
if ( !pl3e )
goto out;
@@ -5391,7 +5399,7 @@ int map_pages_to_xen(
free_xen_pagetable(l2mfn);
}
- pl2e = virt_to_xen_l2e(virt);
+ pl2e = virt_to_xen_l2e_cpu(virt, cpu);
if ( !pl2e )
goto out;
@@ -5437,7 +5445,7 @@ int map_pages_to_xen(
/* Normal page mapping. */
if ( !(l2e_get_flags(*pl2e) & _PAGE_PRESENT) )
{
- pl1e = virt_to_xen_l1e(virt);
+ pl1e = virt_to_xen_l1e_cpu(virt, cpu);
if ( pl1e == NULL )
goto out;
}
@@ -5623,6 +5631,16 @@ int map_pages_to_xen(
return rc;
}
+int map_pages_to_xen(
+ unsigned long virt,
+ mfn_t mfn,
+ unsigned long nr_mfns,
+ unsigned int flags)
+{
+ return map_pages_to_xen_cpu(virt, mfn, nr_mfns, flags, smp_processor_id());
+}
+
+
int __init populate_pt_range(unsigned long virt, unsigned long nr_mfns)
{
return map_pages_to_xen(virt, INVALID_MFN, nr_mfns, MAP_SMALL_PAGES);
@@ -5640,7 +5658,8 @@ int __init populate_pt_range(unsigned long virt, unsigned long nr_mfns)
*
* It is an error to call with present flags over an unpopulated range.
*/
-int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf)
+int modify_xen_mappings_cpu(unsigned long s, unsigned long e, unsigned int nf,
+ unsigned int cpu)
{
bool global = s < PERCPU_VIRT_START ||
s >= PERCPU_VIRT_SLOT(PERCPU_SLOTS);
@@ -5658,6 +5677,9 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf)
ASSERT(global ||
(e >= PERCPU_VIRT_START && e < PERCPU_VIRT_SLOT(PERCPU_SLOTS)));
+ /* Only allow modifying remote page-tables if the CPU is not online. */
+ ASSERT(cpu == smp_processor_id() || !cpu_online(cpu));
+
/* Set of valid PTE bits which may be altered. */
#define FLAGS_MASK (_PAGE_NX|_PAGE_DIRTY|_PAGE_ACCESSED|_PAGE_RW|_PAGE_PRESENT)
nf &= FLAGS_MASK;
@@ -5674,7 +5696,7 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf)
UNMAP_DOMAIN_PAGE(pl2e);
UNMAP_DOMAIN_PAGE(pl3e);
- pl3e = virt_to_xen_l3e(v);
+ pl3e = virt_to_xen_l3e_cpu(v, cpu);
if ( !pl3e )
goto out;
@@ -5927,6 +5949,11 @@ int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf)
#undef flush_area
+int modify_xen_mappings(unsigned long s, unsigned long e, unsigned int nf)
+{
+ return modify_xen_mappings_cpu(s, e, nf, smp_processor_id());
+}
+
int destroy_xen_mappings(unsigned long s, unsigned long e)
{
return modify_xen_mappings(s, e, _PAGE_NONE);
--
2.45.2