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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v6 07/44] x86/mm: have init_xen_l4_slots() take a vCPU in place of the domain
A later change gives the vCPUs of some domains per-domain areas of
their own, and slot 260 of a table private to one vCPU must then hold
that vCPU's L3. Eventually, all guest types may be able to support
either per-domain L3s or per-vCPU L3s.
HVM domains always have one root page table per vCPU; this does not
change. So init_xen_l4_slots() needs the appropriate L3 at vCPU
creation, either the domain-wide L3 or the per-vCPU L3.
PV domains with a domain-wide L3 should behave as now: the Xen slots
of guest root pagetables need the domain-wide L3 installed. But PV
guests with per-vCPU page tables can never run directly on guest
pagetables; they will always need some separate page table, which can
be initialized with the per-vCPU L3.
So, create two versions of init_xen_l4_slots(). The first is used in
contexts where we may be initializing a non-guest root, and must have
a vCPU L3 if per-vCPU L3s are in use; this takes a vCPU as an
argument. The second is used for roots that all of a domain's vCPUs
share (a PV guest's own L4s, and their shadows), which only need an
L3 if domain-wide L3s are in use; this takes a domain as an argument.
Both wrap an internal function, which takes a domain and an L3
pointer, and leaves the slot empty if this pointer is NULL. At the
moment, both always pass on the domain-wide L3, but in the future this
will change if the guest is using per-vCPU pagetables.
Otherwise no functional change: slot 260 still gets the domain's
per-domain L3.
Assisted-by: Claude Code:claude-opus-5-5
Signed-off-by: George Dunlap <gwd@xxxxxxxxxxxxxx>
---
Changes in v6:
- Add init_xen_l4_slots_pv() form, which only takes a domain as an
argument; promote_l4_table(), the PV dom0 builder and the shadows of
PV guests' L4s use it, so promote_l4_table() no longer needs vCPU 0.
Changes in v5:
- promote_l4_table() checks for vCPU 0 itself, now that "x86/mm: refuse
to promote an L4 while the domain has no per-domain L3" tests for the
L3 instead.
Changes in v4:
- New in this version, split out of "x86/hvm: introduce per-vCPU L3
page-table": init_xen_l4_slots() takes a vCPU in place of the domain
(Roger, Jan).
- Reflow promote_l4_table()'s call to init_xen_l4_slots() (Jan).
---
xen/arch/x86/include/asm/mm.h | 4 +++-
xen/arch/x86/mm.c | 35 +++++++++++++++++++++++++++++-----
xen/arch/x86/mm/hap/hap.c | 2 +-
xen/arch/x86/mm/shadow/hvm.c | 2 +-
xen/arch/x86/mm/shadow/multi.c | 5 +++--
xen/arch/x86/pv/dom0_build.c | 4 ++--
xen/arch/x86/pv/domain.c | 2 +-
7 files changed, 41 insertions(+), 13 deletions(-)
diff --git a/xen/arch/x86/include/asm/mm.h b/xen/arch/x86/include/asm/mm.h
index e85a6db203..0d2cecf1c7 100644
--- a/xen/arch/x86/include/asm/mm.h
+++ b/xen/arch/x86/include/asm/mm.h
@@ -370,7 +370,9 @@ int devalidate_page(struct page_info *page, unsigned long
type,
void init_xen_pae_l2_slots(l2_pgentry_t *l2t, const struct domain *d);
void init_xen_l4_slots(l4_pgentry_t *l4t, mfn_t l4mfn,
- const struct domain *d, mfn_t sl4mfn, bool ro_mpt);
+ const struct vcpu *v, mfn_t sl4mfn, bool ro_mpt);
+void init_xen_l4_slots_pv(l4_pgentry_t *l4t, mfn_t l4mfn,
+ const struct domain *d, mfn_t sl4mfn, bool ro_mpt);
bool fill_ro_mpt(mfn_t mfn);
void zap_ro_mpt(mfn_t mfn);
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 61bd4aa02a..10106d9f03 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -1693,8 +1693,10 @@ static int promote_l3_table(struct page_info *page)
* appropriate slots. Pagetables not shared with guests will gain the
* extended directmap.
*/
-void init_xen_l4_slots(l4_pgentry_t *l4t, mfn_t l4mfn,
- const struct domain *d, mfn_t sl4mfn, bool ro_mpt)
+static void _init_xen_l4_slots(l4_pgentry_t *l4t, mfn_t l4mfn,
+ const struct domain *d,
+ const struct page_info *l3_pg,
+ mfn_t sl4mfn, bool ro_mpt)
{
/*
* PV vcpus need a shortened directmap. HVM and Idle vcpus get the full
@@ -1723,7 +1725,7 @@ void init_xen_l4_slots(l4_pgentry_t *l4t, mfn_t l4mfn,
/* Slot 260: Per-domain mappings. */
l4t[l4_table_offset(PERDOMAIN_VIRT_START)] =
- l4e_from_page(d->arch.perdomain_l3_pg, __PAGE_HYPERVISOR_RW);
+ l3_pg ? l4e_from_page(l3_pg, __PAGE_HYPERVISOR_RW) : l4e_empty();
/* Slot 4: Per-domain mappings mirror. */
BUILD_BUG_ON(IS_ENABLED(CONFIG_PV32) &&
@@ -1770,6 +1772,29 @@ void init_xen_l4_slots(l4_pgentry_t *l4t, mfn_t l4mfn,
}
}
+/*
+ * v is the vCPU the table is private to. For shared root pagetables, use
+ * init_xen_l4_slots_pv().
+ */
+void init_xen_l4_slots(l4_pgentry_t *l4t, mfn_t l4mfn,
+ const struct vcpu *v, mfn_t sl4mfn, bool ro_mpt)
+{
+ const struct domain *d = v->domain;
+
+ _init_xen_l4_slots(l4t, l4mfn, d, d->arch.perdomain_l3_pg, sl4mfn, ro_mpt);
+}
+
+/*
+ * This is a version of init_xen_l4_slots for shared root pagetables;
+ * it only propagates domain-wide perdomain L3s, and so only needs a
+ * domain pointer.
+ */
+void init_xen_l4_slots_pv(l4_pgentry_t *l4t, mfn_t l4mfn,
+ const struct domain *d, mfn_t sl4mfn, bool ro_mpt)
+{
+ _init_xen_l4_slots(l4t, l4mfn, d, d->arch.perdomain_l3_pg, sl4mfn, ro_mpt);
+}
+
bool fill_ro_mpt(mfn_t mfn)
{
l4_pgentry_t *l4tab = map_domain_page(mfn);
@@ -1878,8 +1903,8 @@ static int promote_l4_table(struct page_info *page)
if ( !rc )
{
- init_xen_l4_slots(pl4e, l4mfn,
- d, INVALID_MFN, VM_ASSIST(d, m2p_strict));
+ init_xen_l4_slots_pv(pl4e, l4mfn, d, INVALID_MFN,
+ VM_ASSIST(d, m2p_strict));
atomic_inc(&d->arch.pv.nr_l4_pages);
}
unmap_domain_page(pl4e);
diff --git a/xen/arch/x86/mm/hap/hap.c b/xen/arch/x86/mm/hap/hap.c
index 0ede4181a0..aba4f77df9 100644
--- a/xen/arch/x86/mm/hap/hap.c
+++ b/xen/arch/x86/mm/hap/hap.c
@@ -407,7 +407,7 @@ static mfn_t hap_make_monitor_table(struct vcpu *v)
m4mfn = page_to_mfn(pg);
l4e = map_domain_page(m4mfn);
- init_xen_l4_slots(l4e, m4mfn, d, INVALID_MFN, false);
+ init_xen_l4_slots(l4e, m4mfn, v, INVALID_MFN, false);
unmap_domain_page(l4e);
return m4mfn;
diff --git a/xen/arch/x86/mm/shadow/hvm.c b/xen/arch/x86/mm/shadow/hvm.c
index e6fb97c4b6..0b23326214 100644
--- a/xen/arch/x86/mm/shadow/hvm.c
+++ b/xen/arch/x86/mm/shadow/hvm.c
@@ -760,7 +760,7 @@ mfn_t sh_make_monitor_table(const struct vcpu *v, unsigned
int shadow_levels)
* 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, d, INVALID_MFN, false);
+ init_xen_l4_slots(l4e, m4mfn, v, INVALID_MFN, false);
if ( shadow_levels < 4 )
{
diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
index 7f72b4b7b2..1831091b95 100644
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -974,8 +974,9 @@ sh_make_shadow(struct vcpu *v, mfn_t gmfn, u32 shadow_type)
BUILD_BUG_ON(sizeof(l4_pgentry_t) != sizeof(shadow_l4e_t));
- init_xen_l4_slots(l4t, gmfn, d, smfn, (!is_pv_32bit_domain(d) &&
- VM_ASSIST(d, m2p_strict)));
+ init_xen_l4_slots_pv(l4t, gmfn, d, smfn,
+ (!is_pv_32bit_domain(d) &&
+ VM_ASSIST(d, m2p_strict)));
unmap_domain_page(l4t);
}
break;
diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c
index 24f2fa0b7f..dd64af5616 100644
--- a/xen/arch/x86/pv/dom0_build.c
+++ b/xen/arch/x86/pv/dom0_build.c
@@ -724,8 +724,8 @@ static int __init dom0_construct(const struct boot_domain
*bd)
maddr_to_page(mpt_alloc)->u.inuse.type_info = PGT_l4_page_table;
l4start = l4tab = __va(mpt_alloc); mpt_alloc += PAGE_SIZE;
clear_page(l4tab);
- init_xen_l4_slots(l4tab, _mfn(virt_to_mfn(l4start)),
- d, INVALID_MFN, true);
+ init_xen_l4_slots_pv(l4tab, _mfn(virt_to_mfn(l4start)),
+ d, INVALID_MFN, true);
v->arch.guest_table = pagetable_from_paddr(__pa(l4start));
}
else
diff --git a/xen/arch/x86/pv/domain.c b/xen/arch/x86/pv/domain.c
index f3c711b85b..f139d8f83c 100644
--- a/xen/arch/x86/pv/domain.c
+++ b/xen/arch/x86/pv/domain.c
@@ -127,7 +127,7 @@ static int setup_compat_l4(struct vcpu *v)
mfn = page_to_mfn(pg);
l4tab = map_domain_page(mfn);
clear_page(l4tab);
- init_xen_l4_slots(l4tab, mfn, v->domain, INVALID_MFN, false);
+ init_xen_l4_slots(l4tab, mfn, v, INVALID_MFN, false);
unmap_domain_page(l4tab);
/* This page needs to look like a pagetable so that it can be shadowed */
--
2.56.0
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