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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH 14/22] x86/hvm: use a per-pCPU monitor table in shadow mode
Instead of allocating a monitor table for each vCPU when running in HVM shadow
mode, use a per-pCPU monitor table, which gets the per-domain slot updated on
guest context switch.
Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
I've tested this manually, but XenServer builds disable shadow support, so it
possibly hasn't been given the same level of testing as the rest of the
changes.
---
xen/arch/x86/hvm/hvm.c | 7 +++
xen/arch/x86/include/asm/hvm/vcpu.h | 6 ++-
xen/arch/x86/include/asm/paging.h | 18 ++++++++
xen/arch/x86/mm.c | 6 +++
xen/arch/x86/mm/shadow/common.c | 42 +++++++-----------
xen/arch/x86/mm/shadow/hvm.c | 65 ++++++++++++----------------
xen/arch/x86/mm/shadow/multi.c | 66 ++++++++++++++++++-----------
xen/arch/x86/mm/shadow/private.h | 4 +-
8 files changed, 120 insertions(+), 94 deletions(-)
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 3f771bc65677..419d78a79c51 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -141,6 +141,7 @@ void hvm_set_cpu_monitor_table(struct vcpu *v)
ASSERT(pgt);
+ paging_set_cpu_monitor_table(v);
setup_perdomain_slot(v, pgt);
make_cr3(v, _mfn(virt_to_mfn(pgt)));
@@ -150,6 +151,8 @@ void hvm_clear_cpu_monitor_table(struct vcpu *v)
{
/* Poison %cr3, it will be updated when the vCPU is scheduled. */
make_cr3(v, INVALID_MFN);
+
+ paging_clear_cpu_monitor_table(v);
}
static int cf_check cpu_callback(
@@ -1645,6 +1648,10 @@ int hvm_vcpu_initialise(struct vcpu *v)
int rc;
struct domain *d = v->domain;
+#ifdef CONFIG_SHADOW_PAGING
+ v->arch.hvm.shadow_linear_l3 = INVALID_MFN;
+#endif
+
hvm_asid_flush_vcpu(v);
spin_lock_init(&v->arch.hvm.tm_lock);
diff --git a/xen/arch/x86/include/asm/hvm/vcpu.h
b/xen/arch/x86/include/asm/hvm/vcpu.h
index 64c7a6fedea9..f7faaaa21521 100644
--- a/xen/arch/x86/include/asm/hvm/vcpu.h
+++ b/xen/arch/x86/include/asm/hvm/vcpu.h
@@ -149,8 +149,10 @@ struct hvm_vcpu {
uint16_t p2midx;
} fast_single_step;
- /* (MFN) hypervisor page table */
- pagetable_t monitor_table;
+#ifdef CONFIG_SHADOW_PAGING
+ /* Reference to the linear L3 page table. */
+ mfn_t shadow_linear_l3;
+#endif
struct hvm_vcpu_asid n1asid;
diff --git a/xen/arch/x86/include/asm/paging.h
b/xen/arch/x86/include/asm/paging.h
index 8a2a0af40874..c1e188bcd3c0 100644
--- a/xen/arch/x86/include/asm/paging.h
+++ b/xen/arch/x86/include/asm/paging.h
@@ -117,6 +117,8 @@ struct paging_mode {
unsigned long cr3,
paddr_t ga, uint32_t *pfec,
unsigned int *page_order);
+ void (*set_cpu_monitor_table )(struct vcpu *v);
+ void (*clear_cpu_monitor_table)(struct vcpu *v);
#endif
pagetable_t (*update_cr3 )(struct vcpu *v, bool noflush);
@@ -288,6 +290,22 @@ static inline bool paging_flush_tlb(const unsigned long
*vcpu_bitmap)
return current->domain->arch.paging.flush_tlb(vcpu_bitmap);
}
+static inline void paging_set_cpu_monitor_table(struct vcpu *v)
+{
+ const struct paging_mode *mode = paging_get_hostmode(v);
+
+ if ( mode->set_cpu_monitor_table )
+ mode->set_cpu_monitor_table(v);
+}
+
+static inline void paging_clear_cpu_monitor_table(struct vcpu *v)
+{
+ const struct paging_mode *mode = paging_get_hostmode(v);
+
+ if ( mode->clear_cpu_monitor_table )
+ mode->clear_cpu_monitor_table(v);
+}
+
#endif /* CONFIG_HVM */
/* Update all the things that are derived from the guest's CR3.
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 7f2666adaef4..13aa15f4db22 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -534,6 +534,12 @@ void write_ptbase(struct vcpu *v)
}
else
{
+ ASSERT(!is_hvm_domain(d) || !d->arch.asi
+#ifdef CONFIG_HVM
+ || mfn_eq(maddr_to_mfn(v->arch.cr3),
+ virt_to_mfn(this_cpu(monitor_pgt)))
+#endif
+ );
/* Make sure to clear use_pv_cr3 and xen_cr3 before pv_cr3. */
cpu_info->use_pv_cr3 = false;
cpu_info->xen_cr3 = 0;
diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
index 0176e33bc9c7..d31c1db8a1ab 100644
--- a/xen/arch/x86/mm/shadow/common.c
+++ b/xen/arch/x86/mm/shadow/common.c
@@ -2413,16 +2413,12 @@ static void sh_update_paging_modes(struct vcpu *v)
&SHADOW_INTERNAL_NAME(sh_paging_mode, 2);
}
- if ( pagetable_is_null(v->arch.hvm.monitor_table) )
+ if ( mfn_eq(v->arch.hvm.shadow_linear_l3, INVALID_MFN) )
{
- mfn_t mmfn = sh_make_monitor_table(
- v, v->arch.paging.mode->shadow.shadow_levels);
-
- if ( mfn_eq(mmfn, INVALID_MFN) )
+ if ( sh_update_monitor_table(
+ v, v->arch.paging.mode->shadow.shadow_levels) )
return;
- v->arch.hvm.monitor_table = pagetable_from_mfn(mmfn);
- make_cr3(v, mmfn);
hvm_update_host_cr3(v);
}
@@ -2440,8 +2436,8 @@ static void sh_update_paging_modes(struct vcpu *v)
(v->arch.paging.mode->shadow.shadow_levels !=
old_mode->shadow.shadow_levels) )
{
- /* Need to make a new monitor table for the new mode */
- mfn_t new_mfn, old_mfn;
+ /* Might need to make a new L3 linear table for the new mode */
+ mfn_t old_mfn;
if ( v != current && vcpu_runnable(v) )
{
@@ -2455,24 +2451,21 @@ static void sh_update_paging_modes(struct vcpu *v)
return;
}
- old_mfn = pagetable_get_mfn(v->arch.hvm.monitor_table);
- v->arch.hvm.monitor_table = pagetable_null();
- new_mfn = sh_make_monitor_table(
- v, v->arch.paging.mode->shadow.shadow_levels);
- if ( mfn_eq(new_mfn, INVALID_MFN) )
+ old_mfn = v->arch.hvm.shadow_linear_l3;
+ v->arch.hvm.shadow_linear_l3 = INVALID_MFN;
+ if ( sh_update_monitor_table(
+ v, v->arch.paging.mode->shadow.shadow_levels) )
{
sh_destroy_monitor_table(v, old_mfn,
old_mode->shadow.shadow_levels);
return;
}
- v->arch.hvm.monitor_table = pagetable_from_mfn(new_mfn);
- SHADOW_PRINTK("new monitor table %"PRI_mfn "\n",
- mfn_x(new_mfn));
+ SHADOW_PRINTK("new L3 linear table %"PRI_mfn "\n",
+ mfn_x(v->arch.hvm.shadow_linear_l3));
/* Don't be running on the old monitor table when we
* pull it down! Switch CR3, and warn the HVM code that
* its host cr3 has changed. */
- make_cr3(v, new_mfn);
if ( v == current )
write_ptbase(v);
hvm_update_host_cr3(v);
@@ -2781,16 +2774,13 @@ void shadow_vcpu_teardown(struct vcpu *v)
sh_detach_old_tables(v);
#ifdef CONFIG_HVM
- if ( shadow_mode_external(d) )
+ if ( shadow_mode_external(d) &&
+ !mfn_eq(v->arch.hvm.shadow_linear_l3, INVALID_MFN) )
{
- mfn_t mfn = pagetable_get_mfn(v->arch.hvm.monitor_table);
-
- if ( mfn_x(mfn) )
- sh_destroy_monitor_table(
- v, mfn,
+ sh_destroy_monitor_table(
+ v, v->arch.hvm.shadow_linear_l3,
v->arch.paging.mode->shadow.shadow_levels);
-
- v->arch.hvm.monitor_table = pagetable_null();
+ v->arch.hvm.shadow_linear_l3 = INVALID_MFN;
}
#endif
diff --git a/xen/arch/x86/mm/shadow/hvm.c b/xen/arch/x86/mm/shadow/hvm.c
index 93922a71e511..15c75cf766bb 100644
--- a/xen/arch/x86/mm/shadow/hvm.c
+++ b/xen/arch/x86/mm/shadow/hvm.c
@@ -736,30 +736,15 @@ bool cf_check shadow_flush_tlb(const unsigned long
*vcpu_bitmap)
return true;
}
-mfn_t sh_make_monitor_table(const struct vcpu *v, unsigned int shadow_levels)
+int sh_update_monitor_table(struct vcpu *v, unsigned int shadow_levels)
{
struct domain *d = v->domain;
- mfn_t m4mfn;
- l4_pgentry_t *l4e;
- ASSERT(!pagetable_get_pfn(v->arch.hvm.monitor_table));
+ ASSERT(mfn_eq(v->arch.hvm.shadow_linear_l3, INVALID_MFN));
/* Guarantee we can get the memory we need */
- if ( !shadow_prealloc(d, SH_type_monitor_table, CONFIG_PAGING_LEVELS) )
- return INVALID_MFN;
-
- m4mfn = shadow_alloc(d, SH_type_monitor_table, 0);
- mfn_to_page(m4mfn)->shadow_flags = 4;
-
- l4e = map_domain_page(m4mfn);
-
- /*
- * Create a self-linear mapping, but no shadow-linear mapping. A
- * shadow-linear mapping will either be inserted below when creating
- * lower level monitor tables, or later in sh_update_cr3().
- */
- init_xen_l4_slots(l4e, m4mfn, INVALID_MFN, d->arch.perdomain_l3_pg,
- false, true, false);
+ if ( !shadow_prealloc(d, SH_type_monitor_table, CONFIG_PAGING_LEVELS - 1) )
+ return -ENOMEM;
if ( shadow_levels < 4 )
{
@@ -773,52 +758,54 @@ mfn_t sh_make_monitor_table(const struct vcpu *v,
unsigned int shadow_levels)
*/
m3mfn = shadow_alloc(d, SH_type_monitor_table, 0);
mfn_to_page(m3mfn)->shadow_flags = 3;
- l4e[l4_table_offset(SH_LINEAR_PT_VIRT_START)]
- = l4e_from_mfn(m3mfn, __PAGE_HYPERVISOR_RW);
m2mfn = shadow_alloc(d, SH_type_monitor_table, 0);
mfn_to_page(m2mfn)->shadow_flags = 2;
l3e = map_domain_page(m3mfn);
l3e[0] = l3e_from_mfn(m2mfn, __PAGE_HYPERVISOR_RW);
unmap_domain_page(l3e);
- }
- unmap_domain_page(l4e);
+ v->arch.hvm.shadow_linear_l3 = m3mfn;
+
+ /*
+ * If the vCPU is not the current one the L4 entry will be updated on
+ * context switch.
+ */
+ if ( v == current )
+ this_cpu(monitor_pgt)[l4_table_offset(SH_LINEAR_PT_VIRT_START)]
+ = l4e_from_mfn(m3mfn, __PAGE_HYPERVISOR_RW);
+ }
+ else if ( v == current )
+ /* The shadow linear mapping will be inserted in sh_update_cr3(). */
+ this_cpu(monitor_pgt)[l4_table_offset(SH_LINEAR_PT_VIRT_START)]
+ = l4e_empty();
- return m4mfn;
+ return 0;
}
-void sh_destroy_monitor_table(const struct vcpu *v, mfn_t mmfn,
+void sh_destroy_monitor_table(const struct vcpu *v, mfn_t m3mfn,
unsigned int shadow_levels)
{
struct domain *d = v->domain;
- ASSERT(mfn_to_page(mmfn)->u.sh.type == SH_type_monitor_table);
-
if ( shadow_levels < 4 )
{
- mfn_t m3mfn;
- l4_pgentry_t *l4e = map_domain_page(mmfn);
- l3_pgentry_t *l3e;
- unsigned int linear_slot = l4_table_offset(SH_LINEAR_PT_VIRT_START);
+ l3_pgentry_t *l3e = map_domain_page(m3mfn);
+
+ ASSERT(!mfn_eq(m3mfn, INVALID_MFN));
+ ASSERT(mfn_to_page(m3mfn)->u.sh.type == SH_type_monitor_table);
/*
* Need to destroy the l3 and l2 monitor pages used
* for the linear map.
*/
- ASSERT(l4e_get_flags(l4e[linear_slot]) & _PAGE_PRESENT);
- m3mfn = l4e_get_mfn(l4e[linear_slot]);
- l3e = map_domain_page(m3mfn);
ASSERT(l3e_get_flags(l3e[0]) & _PAGE_PRESENT);
shadow_free(d, l3e_get_mfn(l3e[0]));
unmap_domain_page(l3e);
shadow_free(d, m3mfn);
-
- unmap_domain_page(l4e);
}
-
- /* Put the memory back in the pool */
- shadow_free(d, mmfn);
+ else
+ ASSERT(mfn_eq(m3mfn, INVALID_MFN));
}
/**************************************************************************/
diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
index 0def0c073ca8..68c59233794f 100644
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -3007,6 +3007,32 @@ static unsigned long cf_check sh_gva_to_gfn(
return gfn_x(gfn);
}
+static void cf_check set_cpu_monitor_table(struct vcpu *v)
+{
+ root_pgentry_t *pgt = this_cpu(monitor_pgt);
+
+ virt_to_page(pgt)->shadow_flags = 4;
+
+ /* Setup linear L3 entry. */
+ if ( !mfn_eq(v->arch.hvm.shadow_linear_l3, INVALID_MFN) )
+ pgt[l4_table_offset(SH_LINEAR_PT_VIRT_START)] =
+ l4e_from_mfn(v->arch.hvm.shadow_linear_l3, __PAGE_HYPERVISOR_RW);
+ else
+ pgt[l4_table_offset(SH_LINEAR_PT_VIRT_START)] =
+ l4e_from_pfn(
+ pagetable_get_pfn(v->arch.paging.shadow.shadow_table[0]),
+ __PAGE_HYPERVISOR_RW);
+}
+
+static void cf_check clear_cpu_monitor_table(struct vcpu *v)
+{
+ root_pgentry_t *pgt = this_cpu(monitor_pgt);
+
+ virt_to_page(pgt)->shadow_flags = 0;
+
+ pgt[l4_table_offset(SH_LINEAR_PT_VIRT_START)] = l4e_empty();
+}
+
#endif /* CONFIG_HVM */
static inline void
@@ -3033,8 +3059,11 @@ sh_update_linear_entries(struct vcpu *v)
*/
/* Don't try to update the monitor table if it doesn't exist */
- if ( !shadow_mode_external(d) ||
- pagetable_get_pfn(v->arch.hvm.monitor_table) == 0 )
+ if ( !shadow_mode_external(d)
+#if SHADOW_PAGING_LEVELS == 3
+ || mfn_eq(v->arch.hvm.shadow_linear_l3, INVALID_MFN)
+#endif
+ )
return;
#if !defined(CONFIG_HVM)
@@ -3051,17 +3080,6 @@ sh_update_linear_entries(struct vcpu *v)
pagetable_get_pfn(v->arch.paging.shadow.shadow_table[0]),
__PAGE_HYPERVISOR_RW);
}
- else
- {
- l4_pgentry_t *ml4e;
-
- ml4e = map_domain_page(pagetable_get_mfn(v->arch.hvm.monitor_table));
- ml4e[l4_table_offset(SH_LINEAR_PT_VIRT_START)] =
- l4e_from_pfn(
- pagetable_get_pfn(v->arch.paging.shadow.shadow_table[0]),
- __PAGE_HYPERVISOR_RW);
- unmap_domain_page(ml4e);
- }
#elif SHADOW_PAGING_LEVELS == 3
@@ -3087,16 +3105,8 @@ sh_update_linear_entries(struct vcpu *v)
+ l2_linear_offset(SH_LINEAR_PT_VIRT_START);
else
{
- mfn_t l3mfn, l2mfn;
- l4_pgentry_t *ml4e;
- l3_pgentry_t *ml3e;
- int linear_slot = shadow_l4_table_offset(SH_LINEAR_PT_VIRT_START);
- ml4e =
map_domain_page(pagetable_get_mfn(v->arch.hvm.monitor_table));
-
- ASSERT(l4e_get_flags(ml4e[linear_slot]) & _PAGE_PRESENT);
- l3mfn = l4e_get_mfn(ml4e[linear_slot]);
- ml3e = map_domain_page(l3mfn);
- unmap_domain_page(ml4e);
+ mfn_t l2mfn;
+ l3_pgentry_t *ml3e = map_domain_page(v->arch.hvm.shadow_linear_l3);
ASSERT(l3e_get_flags(ml3e[0]) & _PAGE_PRESENT);
l2mfn = l3e_get_mfn(ml3e[0]);
@@ -3341,9 +3351,13 @@ static pagetable_t cf_check sh_update_cr3(struct vcpu
*v, bool noflush)
///
/// v->arch.cr3
///
- if ( shadow_mode_external(d) )
+ if ( shadow_mode_external(d) && v == current )
{
- make_cr3(v, pagetable_get_mfn(v->arch.hvm.monitor_table));
+#ifdef CONFIG_HVM
+ make_cr3(v, _mfn(virt_to_mfn(this_cpu(monitor_pgt))));
+#else
+ ASSERT_UNREACHABLE();
+#endif
}
#if SHADOW_PAGING_LEVELS == 4
else // not shadow_mode_external...
@@ -4106,6 +4120,8 @@ const struct paging_mode sh_paging_mode = {
.invlpg = sh_invlpg,
#ifdef CONFIG_HVM
.gva_to_gfn = sh_gva_to_gfn,
+ .set_cpu_monitor_table = set_cpu_monitor_table,
+ .clear_cpu_monitor_table = clear_cpu_monitor_table,
#endif
.update_cr3 = sh_update_cr3,
.guest_levels = GUEST_PAGING_LEVELS,
diff --git a/xen/arch/x86/mm/shadow/private.h b/xen/arch/x86/mm/shadow/private.h
index a5fc3a7676eb..6743aeefe12e 100644
--- a/xen/arch/x86/mm/shadow/private.h
+++ b/xen/arch/x86/mm/shadow/private.h
@@ -420,8 +420,8 @@ void shadow_unhook_mappings(struct domain *d, mfn_t smfn,
int user_only);
* sh_{make,destroy}_monitor_table() depend only on the number of shadow
* levels.
*/
-mfn_t sh_make_monitor_table(const struct vcpu *v, unsigned int shadow_levels);
-void sh_destroy_monitor_table(const struct vcpu *v, mfn_t mmfn,
+int sh_update_monitor_table(struct vcpu *v, unsigned int shadow_levels);
+void sh_destroy_monitor_table(const struct vcpu *v, mfn_t m3mfn,
unsigned int shadow_levels);
/* VRAM dirty tracking helpers. */
--
2.45.2
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