[RFC PATCH v11 16/29] KVM: Allow arch code to track number of memslot address spaces per VM

From: Sean Christopherson
Date: Tue Jul 18 2023 - 19:51:40 EST


Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/powerpc/kvm/book3s_hv.c | 2 +-
arch/x86/include/asm/kvm_host.h | 8 +++++++-
arch/x86/kvm/debugfs.c | 2 +-
arch/x86/kvm/mmu/mmu.c | 8 ++++----
arch/x86/kvm/mmu/tdp_mmu.c | 2 +-
arch/x86/kvm/x86.c | 2 +-
include/linux/kvm_host.h | 17 +++++++++++------
virt/kvm/dirty_ring.c | 2 +-
virt/kvm/kvm_main.c | 24 ++++++++++++------------
9 files changed, 39 insertions(+), 28 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 130bafdb1430..9b0eaa17275a 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -6084,7 +6084,7 @@ static int kvmhv_svm_off(struct kvm *kvm)
}

srcu_idx = srcu_read_lock(&kvm->srcu);
- for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+ for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
struct kvm_memory_slot *memslot;
struct kvm_memslots *slots = __kvm_memslots(kvm, i);
int bkt;
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 7a905e033932..08b44544a330 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -2105,9 +2105,15 @@ enum {
#define HF_SMM_MASK (1 << 1)
#define HF_SMM_INSIDE_NMI_MASK (1 << 2)

-# define KVM_ADDRESS_SPACE_NUM 2
+# define KVM_MAX_NR_ADDRESS_SPACES 2
# define kvm_arch_vcpu_memslots_id(vcpu) ((vcpu)->arch.hflags & HF_SMM_MASK ? 1 : 0)
# define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, (role).smm)
+
+static inline int kvm_arch_nr_memslot_as_ids(struct kvm *kvm)
+{
+ return KVM_MAX_NR_ADDRESS_SPACES;
+}
+
#else
# define kvm_memslots_for_spte_role(kvm, role) __kvm_memslots(kvm, 0)
#endif
diff --git a/arch/x86/kvm/debugfs.c b/arch/x86/kvm/debugfs.c
index ee8c4c3496ed..42026b3f3ff3 100644
--- a/arch/x86/kvm/debugfs.c
+++ b/arch/x86/kvm/debugfs.c
@@ -111,7 +111,7 @@ static int kvm_mmu_rmaps_stat_show(struct seq_file *m, void *v)
mutex_lock(&kvm->slots_lock);
write_lock(&kvm->mmu_lock);

- for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+ for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
int bkt;

slots = __kvm_memslots(kvm, i);
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 4cf73a579ee1..05943ccb55a4 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -3801,7 +3801,7 @@ static int mmu_first_shadow_root_alloc(struct kvm *kvm)
kvm_page_track_write_tracking_enabled(kvm))
goto out_success;

- for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+ for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
slots = __kvm_memslots(kvm, i);
kvm_for_each_memslot(slot, bkt, slots) {
/*
@@ -6351,7 +6351,7 @@ static bool kvm_rmap_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_e
if (!kvm_memslots_have_rmaps(kvm))
return flush;

- for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+ for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
slots = __kvm_memslots(kvm, i);

kvm_for_each_memslot_in_gfn_range(&iter, slots, gfn_start, gfn_end) {
@@ -6391,7 +6391,7 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
flush = kvm_rmap_zap_gfn_range(kvm, gfn_start, gfn_end);

if (tdp_mmu_enabled) {
- for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++)
+ for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++)
flush = kvm_tdp_mmu_zap_leafs(kvm, i, gfn_start,
gfn_end, true, flush);
}
@@ -6855,7 +6855,7 @@ void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen)
* modifier prior to checking for a wrap of the MMIO generation so
* that a wrap in any address space is detected.
*/
- gen &= ~((u64)KVM_ADDRESS_SPACE_NUM - 1);
+ gen &= ~((u64)kvm_arch_nr_memslot_as_ids(kvm) - 1);

/*
* The very rare case: if the MMIO generation number has wrapped,
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 6250bd3d20c1..70052f59cfdf 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -905,7 +905,7 @@ void kvm_tdp_mmu_zap_all(struct kvm *kvm)
* is being destroyed or the userspace VMM has exited. In both cases,
* KVM_RUN is unreachable, i.e. no vCPUs will ever service the request.
*/
- for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+ for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
for_each_tdp_mmu_root_yield_safe(kvm, root, i)
tdp_mmu_zap_root(kvm, root, false);
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index dd7cefe78815..463ecf70cec0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -12419,7 +12419,7 @@ void __user * __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa,
hva = slot->userspace_addr;
}

- for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+ for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
struct kvm_userspace_memory_region2 m;

m.slot = id | (i << 16);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 5839ef44e145..091bc89ae805 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -80,8 +80,8 @@
/* Two fragments for cross MMIO pages. */
#define KVM_MAX_MMIO_FRAGMENTS 2

-#ifndef KVM_ADDRESS_SPACE_NUM
-#define KVM_ADDRESS_SPACE_NUM 1
+#ifndef KVM_MAX_NR_ADDRESS_SPACES
+#define KVM_MAX_NR_ADDRESS_SPACES 1
#endif

/*
@@ -693,7 +693,12 @@ bool kvm_arch_irqchip_in_kernel(struct kvm *kvm);
#define KVM_MEM_SLOTS_NUM SHRT_MAX
#define KVM_USER_MEM_SLOTS (KVM_MEM_SLOTS_NUM - KVM_INTERNAL_MEM_SLOTS)

-#if KVM_ADDRESS_SPACE_NUM == 1
+#if KVM_MAX_NR_ADDRESS_SPACES == 1
+static inline int kvm_arch_nr_memslot_as_ids(struct kvm *kvm)
+{
+ return KVM_MAX_NR_ADDRESS_SPACES;
+}
+
static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu)
{
return 0;
@@ -748,9 +753,9 @@ struct kvm {
struct mm_struct *mm; /* userspace tied to this vm */
unsigned long nr_memslot_pages;
/* The two memslot sets - active and inactive (per address space) */
- struct kvm_memslots __memslots[KVM_ADDRESS_SPACE_NUM][2];
+ struct kvm_memslots __memslots[KVM_MAX_NR_ADDRESS_SPACES][2];
/* The current active memslot set for each address space */
- struct kvm_memslots __rcu *memslots[KVM_ADDRESS_SPACE_NUM];
+ struct kvm_memslots __rcu *memslots[KVM_MAX_NR_ADDRESS_SPACES];
struct xarray vcpu_array;
/*
* Protected by slots_lock, but can be read outside if an
@@ -1000,7 +1005,7 @@ void kvm_put_kvm_no_destroy(struct kvm *kvm);

static inline struct kvm_memslots *__kvm_memslots(struct kvm *kvm, int as_id)
{
- as_id = array_index_nospec(as_id, KVM_ADDRESS_SPACE_NUM);
+ as_id = array_index_nospec(as_id, KVM_MAX_NR_ADDRESS_SPACES);
return srcu_dereference_check(kvm->memslots[as_id], &kvm->srcu,
lockdep_is_held(&kvm->slots_lock) ||
!refcount_read(&kvm->users_count));
diff --git a/virt/kvm/dirty_ring.c b/virt/kvm/dirty_ring.c
index c1cd7dfe4a90..86d267db87bb 100644
--- a/virt/kvm/dirty_ring.c
+++ b/virt/kvm/dirty_ring.c
@@ -58,7 +58,7 @@ static void kvm_reset_dirty_gfn(struct kvm *kvm, u32 slot, u64 offset, u64 mask)
as_id = slot >> 16;
id = (u16)slot;

- if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
+ if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_USER_MEM_SLOTS)
return;

memslot = id_to_memslot(__kvm_memslots(kvm, as_id), id);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a8686e8473a4..ee331cf8ba54 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -582,7 +582,7 @@ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm,

idx = srcu_read_lock(&kvm->srcu);

- for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+ for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
struct interval_tree_node *node;

slots = __kvm_memslots(kvm, i);
@@ -1206,7 +1206,7 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
goto out_err_no_irq_srcu;

refcount_set(&kvm->users_count, 1);
- for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+ for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
for (j = 0; j < 2; j++) {
slots = &kvm->__memslots[i][j];

@@ -1349,7 +1349,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
#endif
kvm_arch_destroy_vm(kvm);
kvm_destroy_devices(kvm);
- for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+ for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
kvm_free_memslots(kvm, &kvm->__memslots[i][0]);
kvm_free_memslots(kvm, &kvm->__memslots[i][1]);
}
@@ -1632,7 +1632,7 @@ static void kvm_swap_active_memslots(struct kvm *kvm, int as_id)
* space 0 will use generations 0, 2, 4, ... while address space 1 will
* use generations 1, 3, 5, ...
*/
- gen += KVM_ADDRESS_SPACE_NUM;
+ gen += kvm_arch_nr_memslot_as_ids(kvm);

kvm_arch_memslots_updated(kvm, gen);

@@ -2002,7 +2002,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
(mem->gmem_offset & (PAGE_SIZE - 1) ||
mem->gmem_offset + mem->memory_size < mem->gmem_offset))
return -EINVAL;
- if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_MEM_SLOTS_NUM)
+ if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_MEM_SLOTS_NUM)
return -EINVAL;
if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr)
return -EINVAL;
@@ -2138,7 +2138,7 @@ int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log,

as_id = log->slot >> 16;
id = (u16)log->slot;
- if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
+ if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_USER_MEM_SLOTS)
return -EINVAL;

slots = __kvm_memslots(kvm, as_id);
@@ -2200,7 +2200,7 @@ static int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log)

as_id = log->slot >> 16;
id = (u16)log->slot;
- if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
+ if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_USER_MEM_SLOTS)
return -EINVAL;

slots = __kvm_memslots(kvm, as_id);
@@ -2312,7 +2312,7 @@ static int kvm_clear_dirty_log_protect(struct kvm *kvm,

as_id = log->slot >> 16;
id = (u16)log->slot;
- if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS)
+ if (as_id >= kvm_arch_nr_memslot_as_ids(kvm) || id >= KVM_USER_MEM_SLOTS)
return -EINVAL;

if (log->first_page & 63)
@@ -2406,7 +2406,7 @@ static __always_inline void kvm_handle_gfn_range(struct kvm *kvm,
gfn_range.arg.raw = range->arg.raw;
gfn_range.may_block = range->may_block;

- for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+ for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
slots = __kvm_memslots(kvm, i);

kvm_for_each_memslot_in_gfn_range(&iter, slots, range->start, range->end) {
@@ -4725,9 +4725,9 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
case KVM_CAP_IRQ_ROUTING:
return KVM_MAX_IRQ_ROUTES;
#endif
-#if KVM_ADDRESS_SPACE_NUM > 1
+#if KVM_MAX_NR_ADDRESS_SPACES > 1
case KVM_CAP_MULTI_ADDRESS_SPACE:
- return KVM_ADDRESS_SPACE_NUM;
+ return KVM_MAX_NR_ADDRESS_SPACES;
#endif
case KVM_CAP_NR_MEMSLOTS:
return KVM_USER_MEM_SLOTS;
@@ -4827,7 +4827,7 @@ bool kvm_are_all_memslots_empty(struct kvm *kvm)

lockdep_assert_held(&kvm->slots_lock);

- for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+ for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
if (!kvm_memslots_empty(__kvm_memslots(kvm, i)))
return false;
}
--
2.41.0.255.g8b1d071c50-goog