Add some of the data to move from one plane to the other within a VM,
typically from plane N to plane 0.
There is quite some difference here because while separate planes provide
very little of the vm file descriptor functionality, they are almost fully
functional vCPUs except that non-zero planes(*) can only be ran indirectly
through the initial plane.
Therefore, vCPUs use struct kvm_vcpu for all planes, with just a couple
fields that will be added later and will only be valid for plane 0. At
the VM level instead plane info is stored in a completely different struct.
For now struct kvm_plane has no architecture-specific counterpart, but this
may change in the future if needed. It's possible for example that some MMU
info becomes per-plane in order to support per-plane RWX permissions.
(*) I will restrain from calling them astral planes.
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
include/linux/kvm_host.h | 17 ++++++++++++++++-
include/linux/kvm_types.h | 1 +
virt/kvm/kvm_main.c | 32 ++++++++++++++++++++++++++++++++
3 files changed, 49 insertions(+), 1 deletion(-)
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c8f1facdb600..0e16c34080ef 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -84,6 +84,10 @@
#define KVM_MAX_NR_ADDRESS_SPACES 1
#endif
+#ifndef KVM_MAX_VCPU_PLANES
+#define KVM_MAX_VCPU_PLANES 1
+#endif
+
/*
* For the normal pfn, the highest 12 bits should be zero,
* so we can mask bit 62 ~ bit 52 to indicate the error pfn,
@@ -332,7 +336,8 @@ struct kvm_vcpu {
#ifdef CONFIG_PROVE_RCU
int srcu_depth;
#endif
- int mode;
+ short plane;
+ short mode;
u64 requests;
unsigned long guest_debug;
@@ -367,6 +372,8 @@ struct kvm_vcpu {
} async_pf;
#endif
+ struct kvm_vcpu *plane0;
+
#ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT
/*
* Cpu relax intercept or pause loop exit optimization
@@ -753,6 +760,11 @@ struct kvm_memslots {
int node_idx;
};
+struct kvm_plane {
+ struct kvm *kvm;
+ int plane;
+};
+
struct kvm {
#ifdef KVM_HAVE_MMU_RWLOCK
rwlock_t mmu_lock;
@@ -777,6 +789,9 @@ struct kvm {
/* The current active memslot set for each address space */
struct kvm_memslots __rcu *memslots[KVM_MAX_NR_ADDRESS_SPACES];
struct xarray vcpu_array;
+
+ struct kvm_plane *planes[KVM_MAX_VCPU_PLANES];
+
/*
* Protected by slots_lock, but can be read outside if an
* incorrect answer is acceptable.
diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h
index 827ecc0b7e10..7d0a86108d1a 100644
--- a/include/linux/kvm_types.h
+++ b/include/linux/kvm_types.h
@@ -11,6 +11,7 @@ struct kvm_interrupt;
struct kvm_irq_routing_table;
struct kvm_memory_slot;
struct kvm_one_reg;
+struct kvm_plane;
struct kvm_run;
struct kvm_userspace_memory_region;
struct kvm_vcpu;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f6c947961b78..67773b6b9576 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1095,9 +1095,22 @@ void __weak kvm_arch_create_vm_debugfs(struct kvm *kvm)
{
}
+static struct kvm_plane *kvm_create_vm_plane(struct kvm *kvm, unsigned plane_id)
+{
+ struct kvm_plane *plane = kzalloc(sizeof(struct kvm_plane), GFP_KERNEL_ACCOUNT);
+
+ if (!plane)
+ return ERR_PTR(-ENOMEM);
+
+ plane->kvm = kvm;
+ plane->plane = plane_id;
+ return plane;
+}
+
static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
{
struct kvm *kvm = kvm_arch_alloc_vm();
+ struct kvm_plane *plane0;
struct kvm_memslots *slots;
int r, i, j;
@@ -1136,6 +1149,13 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
snprintf(kvm->stats_id, sizeof(kvm->stats_id), "kvm-%d",
task_pid_nr(current));
+ plane0 = kvm_create_vm_plane(kvm, 0);
+ if (IS_ERR(plane0)) {
+ r = PTR_ERR(plane0);
+ goto out_err_no_plane0;
+ }
+ kvm->planes[0] = plane0;
+
r = -ENOMEM;
if (init_srcu_struct(&kvm->srcu))
goto out_err_no_srcu;
@@ -1227,6 +1247,8 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
out_err_no_irq_srcu:
cleanup_srcu_struct(&kvm->srcu);
out_err_no_srcu:
+ kfree(kvm->planes[0]);
+out_err_no_plane0:
kvm_arch_free_vm(kvm);
mmdrop(current->mm);
return ERR_PTR(r);
@@ -1253,6 +1275,10 @@ static void kvm_destroy_devices(struct kvm *kvm)
}
}
+static void kvm_destroy_plane(struct kvm_plane *plane)
+{
+}
+
static void kvm_destroy_vm(struct kvm *kvm)
{
int i;
@@ -1309,6 +1335,11 @@ static void kvm_destroy_vm(struct kvm *kvm)
#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
xa_destroy(&kvm->mem_attr_array);
#endif
+ for (i = 0; i < ARRAY_SIZE(kvm->planes); i++) {
+ struct kvm_plane *plane = kvm->planes[i];
+ if (plane)
+ kvm_destroy_plane(plane);
+ }
kvm_arch_free_vm(kvm);
preempt_notifier_dec();
kvm_disable_virtualization();
@@ -4110,6 +4141,7 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, unsigned long id)
}
vcpu->run = page_address(page);
+ vcpu->plane0 = vcpu;
kvm_vcpu_init(vcpu, kvm, id);
r = kvm_arch_vcpu_create(vcpu);
--
2.49.0
