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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v6 05/44] x86/mm: prepare create_perdomain_mapping() for per-vCPU perdomain areas
From: Roger Pau Monné <roger.pau@xxxxxxxxxx>
We want to change per-domain mappings to be per-vCPU mappings. In
preparation for that, we want to arrange that
create_perdomain_mapping() work either with a single perdomain area,
or with a per-vCPU perdomain area.
The remaining callers are already in a vCPU context. This is no
accident: much of the perdomain area has always been laid out in
per-vCPU slices -- each vCPU has its own GDT/LDT window and its own
COMPAT_ARG_XLAT pages -- and each vCPU's slice is set up as that vCPU
is created. For these callers, we just need to change the parameter
from a domain pointer to a vCPU pointer. Once the perdomain area
itself becomes per-vCPU, the same calls will populate the owning
vCPU's own area rather than slices of a shared one.
Note that we cannot yet do a parallel movement of
free_perdomain_mappings(): the per-domain page-table hierarchy is
still a single domain-wide structure shared by all vCPUs, so tearing
it down from a per-vCPU path would pull the mappings out from under
sibling vCPUs (e.g. on a partially failed, retryable
XEN_DOMCTL_max_vcpus), and vCPU-create error paths can rely on domain
destruction to free a partially set up hierarchy. Once a domain's
area is per-vCPU, a later change gives its vCPUs a teardown of their
own; the domain-wide teardown stays for domains with a shared area, PV
ones included.
Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Assisted-by: Claude Code:claude-fable-5, Claude Code:claude-opus-4-8, Claude
Code:claude-opus-5-5
Signed-off-by: George Dunlap <gwd@xxxxxxxxxxxxxx>
---
Changes in v6:
- Rebase over "x86/mm: allocate the per-domain L3 in
arch_domain_create()".
- No longer add an implicit L3 creation in arch_vcpu_create().
Changes in v5:
- Message: the domain-wide mapcache is one pool, not per-vCPU windows:
drop it from the per-vCPU slices, and say "much of" the area.
Changes in v4:
- Message: drop a sentence repeating its paragraph, and say that the
domain-wide teardown stays for domains with a shared area (Roger).
- End the comment in arch_vcpu_create() at the colon (Roger).
Changes in v3:
- Rebased onto staging without the GDT/LDT conversions (for the
HVM-only series): the capture parameters stay, as the PV GDT/LDT
stash still uses them.
Changes in v2:
- Added to the series
Changes since the previously posted version:
- Keep free_perdomain_mappings() (and hence perdomain teardown)
domain-scoped.
- Keep the idle domain without a perdomain area.
- Retitle (was: "x86/mm: switch {create,destroy}_perdomain_mapping()
domain parameter to vCPU"); destroy_perdomain_mapping() was switched
in a separate patch.
- Split the removal of mapcache_domain_init()'s redundant
create_perdomain_mapping() call into its own (preceding) patch.
---
xen/arch/x86/domain_page.c | 6 +++---
xen/arch/x86/include/asm/mm.h | 2 +-
xen/arch/x86/mm.c | 3 ++-
xen/arch/x86/pv/domain.c | 2 +-
xen/arch/x86/x86_64/mm.c | 2 +-
5 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/xen/arch/x86/domain_page.c b/xen/arch/x86/domain_page.c
index f02be1675b..f3e65e2d44 100644
--- a/xen/arch/x86/domain_page.c
+++ b/xen/arch/x86/domain_page.c
@@ -260,15 +260,15 @@ int mapcache_vcpu_init(struct vcpu *v)
if ( ents > dcache->entries )
{
/* Populate page tables. */
- int rc = create_perdomain_mapping(d, MAPCACHE_VIRT_START, ents,
+ int rc = create_perdomain_mapping(v, MAPCACHE_VIRT_START, ents,
NIL(l1_pgentry_t *), NULL);
/* Populate bit maps. */
if ( !rc )
- rc = create_perdomain_mapping(d, (unsigned long)dcache->inuse,
+ rc = create_perdomain_mapping(v, (unsigned long)dcache->inuse,
nr, NULL, NIL(struct page_info *));
if ( !rc )
- rc = create_perdomain_mapping(d, (unsigned long)dcache->garbage,
+ rc = create_perdomain_mapping(v, (unsigned long)dcache->garbage,
nr, NULL, NIL(struct page_info *));
if ( rc )
diff --git a/xen/arch/x86/include/asm/mm.h b/xen/arch/x86/include/asm/mm.h
index 1cdd30f7e2..e85a6db203 100644
--- a/xen/arch/x86/include/asm/mm.h
+++ b/xen/arch/x86/include/asm/mm.h
@@ -607,7 +607,7 @@ int compat_arch_memory_op(unsigned long cmd,
XEN_GUEST_HANDLE_PARAM(void) arg);
#define IS_NIL(ptr) (!((uintptr_t)(ptr) + sizeof(*(ptr))))
struct page_info *allocate_perdomain_l3(struct domain *d);
-int create_perdomain_mapping(struct domain *d, unsigned long va,
+int create_perdomain_mapping(struct vcpu *v, unsigned long va,
unsigned int nr, l1_pgentry_t **pl1tab,
struct page_info **ppg);
void destroy_perdomain_mapping(const struct vcpu *v, unsigned long va,
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index c784c4f726..61bd4aa02a 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -6245,10 +6245,11 @@ struct page_info *allocate_perdomain_l3(struct domain
*d)
return pg;
}
-int create_perdomain_mapping(struct domain *d, unsigned long va,
+int create_perdomain_mapping(struct vcpu *v, unsigned long va,
unsigned int nr, l1_pgentry_t **pl1tab,
struct page_info **ppg)
{
+ struct domain *d = v->domain;
struct page_info *pg;
l3_pgentry_t *l3tab;
l2_pgentry_t *l2tab;
diff --git a/xen/arch/x86/pv/domain.c b/xen/arch/x86/pv/domain.c
index 28ea0742ab..f3c711b85b 100644
--- a/xen/arch/x86/pv/domain.c
+++ b/xen/arch/x86/pv/domain.c
@@ -313,7 +313,7 @@ int switch_compat(struct domain *d)
static int pv_create_gdt_ldt_l1tab(struct vcpu *v)
{
- return create_perdomain_mapping(v->domain, GDT_VIRT_START(v),
+ return create_perdomain_mapping(v, GDT_VIRT_START(v),
1U << GDT_LDT_VCPU_SHIFT,
v->domain->arch.pv.gdt_ldt_l1tab,
NULL);
diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index f467ed426b..7b04537066 100644
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -732,7 +732,7 @@ void __init zap_low_mappings(void)
int setup_compat_arg_xlat(struct vcpu *v)
{
- return create_perdomain_mapping(v->domain, ARG_XLAT_START(v),
+ return create_perdomain_mapping(v, ARG_XLAT_START(v),
PFN_UP(COMPAT_ARG_XLAT_SIZE),
NULL, NIL(struct page_info *));
}
--
2.56.0
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