From: Ashish Kalra <ashish.ka...@amd.com>

Add support for static allocation of the unified Page encryption bitmap by
extending kvm_arch_commit_memory_region() callack to add svm specific x86_ops
which can read the userspace provided memory region/memslots and calculate
the amount of guest RAM managed by the KVM and grow the bitmap based
on that information, i.e. the highest guest PA that is mapped by a memslot.

Signed-off-by: Ashish Kalra <ashish.ka...@amd.com>
---
 arch/x86/include/asm/kvm_host.h |  1 +
 arch/x86/kvm/svm/sev.c          | 35 +++++++++++++++++++++++++++++++++
 arch/x86/kvm/svm/svm.c          |  1 +
 arch/x86/kvm/svm/svm.h          |  1 +
 arch/x86/kvm/x86.c              |  5 +++++
 5 files changed, 43 insertions(+)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index fc74144d5ab0..b573ea85b57e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1254,6 +1254,7 @@ struct kvm_x86_ops {
 
        bool (*apic_init_signal_blocked)(struct kvm_vcpu *vcpu);
        int (*enable_direct_tlbflush)(struct kvm_vcpu *vcpu);
+       void (*commit_memory_region)(struct kvm *kvm, enum kvm_mr_change 
change);
        int (*page_enc_status_hc)(struct kvm *kvm, unsigned long gpa,
                                  unsigned long sz, unsigned long mode);
        int (*get_page_enc_bitmap)(struct kvm *kvm,
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 30efc1068707..c0d7043a0627 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1377,6 +1377,41 @@ static int sev_resize_page_enc_bitmap(struct kvm *kvm, 
unsigned long new_size)
        return 0;
 }
 
+void svm_commit_memory_region(struct kvm *kvm, enum kvm_mr_change change)
+{
+       struct kvm_memslots *slots;
+       struct kvm_memory_slot *memslot;
+       gfn_t start, end = 0;
+
+       spin_lock(&kvm->mmu_lock);
+       if (change == KVM_MR_CREATE) {
+               slots = kvm_memslots(kvm);
+               kvm_for_each_memslot(memslot, slots) {
+                       start = memslot->base_gfn;
+                       end = memslot->base_gfn + memslot->npages;
+                       /*
+                        * KVM memslots is a sorted list, starting with
+                        * the highest mapped guest PA, so pick the topmost
+                        * valid guest PA.
+                        */
+                       if (memslot->npages)
+                               break;
+               }
+       }
+       spin_unlock(&kvm->mmu_lock);
+
+       if (end) {
+               /*
+                * NORE: This callback is invoked in vm ioctl
+                * set_user_memory_region, hence we can use a
+                * mutex here.
+                */
+               mutex_lock(&kvm->lock);
+               sev_resize_page_enc_bitmap(kvm, end);
+               mutex_unlock(&kvm->lock);
+       }
+}
+
 int svm_page_enc_status_hc(struct kvm *kvm, unsigned long gpa,
                                  unsigned long npages, unsigned long enc)
 {
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 501e82f5593c..442adbbb0641 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4015,6 +4015,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 
        .check_nested_events = svm_check_nested_events,
 
+       .commit_memory_region = svm_commit_memory_region,
        .page_enc_status_hc = svm_page_enc_status_hc,
        .get_page_enc_bitmap = svm_get_page_enc_bitmap,
        .set_page_enc_bitmap = svm_set_page_enc_bitmap,
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 2ebdcce50312..fd99e0a5417a 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -406,6 +406,7 @@ int svm_page_enc_status_hc(struct kvm *kvm, unsigned long 
gpa,
                                  unsigned long npages, unsigned long enc);
 int svm_get_page_enc_bitmap(struct kvm *kvm, struct kvm_page_enc_bitmap *bmap);
 int svm_set_page_enc_bitmap(struct kvm *kvm, struct kvm_page_enc_bitmap *bmap);
+void svm_commit_memory_region(struct kvm *kvm, enum kvm_mr_change change);
 
 /* avic.c */
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c4166d7a0493..8938de868d42 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10133,6 +10133,11 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
                kvm_mmu_change_mmu_pages(kvm,
                                kvm_mmu_calculate_default_mmu_pages(kvm));
 
+       if (change == KVM_MR_CREATE || change == KVM_MR_DELETE) {
+               if (kvm_x86_ops.commit_memory_region)
+                       kvm_x86_ops.commit_memory_region(kvm, change);
+       }
+
        /*
         * Dirty logging tracks sptes in 4k granularity, meaning that large
         * sptes have to be split.  If live migration is successful, the guest
-- 
2.17.1

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