[Patch v2 4/4] KVM:SVM: Remove struct enc_region and associated pinned page tracking.

[eric van tassell]

Remove the enc_region structure definition and the code which maintained
it, as they are no longer needed in view of the xarray support we added in
the previous patch.

Leave svm_register_enc_region() and svm_unregister_enc_region() as stubs
since the ioctl is used by qemu and qemu will crash if they do not
return 0.

Co-developed-by: Brijesh Singh <brijesh.si...@amd.com>
Signed-off-by: eric van tassell <eric.vantass...@amd.com>
---
 arch/x86/kvm/svm/sev.c | 117 +----------------------------------------
 arch/x86/kvm/svm/svm.h |   1 -
 2 files changed, 1 insertion(+), 117 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 4a0157254fef..635e15f01edb 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -27,14 +27,6 @@ static unsigned long *sev_asid_bitmap;
 static unsigned long *sev_reclaim_asid_bitmap;
 #define __sme_page_pa(x) __sme_set(page_to_pfn(x) << PAGE_SHIFT)
 
-struct enc_region {
-       struct list_head list;
-       unsigned long npages;
-       struct page **pages;
-       unsigned long uaddr;
-       unsigned long size;
-};
-
 static int sev_flush_asids(void)
 {
        int ret, error = 0;
@@ -182,7 +174,6 @@ static int sev_guest_init(struct kvm *kvm, struct 
kvm_sev_cmd *argp)
 
        sev->active = true;
        sev->asid = asid;
-       INIT_LIST_HEAD(&sev->regions_list);
 
        xa_init(&sev->pages_xarray);
 
@@ -1074,113 +1065,18 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 int svm_register_enc_region(struct kvm *kvm,
                            struct kvm_enc_region *range)
 {
-       struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct enc_region *region;
-       int ret = 0;
-
-       if (!sev_guest(kvm))
-               return -ENOTTY;
-
-       if (range->addr > ULONG_MAX || range->size > ULONG_MAX)
-               return -EINVAL;
-
-       region = kzalloc(sizeof(*region), GFP_KERNEL_ACCOUNT);
-       if (!region)
-               return -ENOMEM;
-
-       region->pages = sev_pin_memory(kvm, range->addr, range->size, 
&region->npages, 1);
-       if (IS_ERR(region->pages)) {
-               ret = PTR_ERR(region->pages);
-               goto e_free;
-       }
-
-       /*
-        * The guest may change the memory encryption attribute from C=0 -> C=1
-        * or vice versa for this memory range. Lets make sure caches are
-        * flushed to ensure that guest data gets written into memory with
-        * correct C-bit.
-        */
-       sev_clflush_pages(region->pages, region->npages);
-
-       region->uaddr = range->addr;
-       region->size = range->size;
-
-       mutex_lock(&kvm->lock);
-       list_add_tail(&region->list, &sev->regions_list);
-       mutex_unlock(&kvm->lock);
-
-       return ret;
-
-e_free:
-       kfree(region);
-       return ret;
-}
-
-static struct enc_region *
-find_enc_region(struct kvm *kvm, struct kvm_enc_region *range)
-{
-       struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct list_head *head = &sev->regions_list;
-       struct enc_region *i;
-
-       list_for_each_entry(i, head, list) {
-               if (i->uaddr == range->addr &&
-                   i->size == range->size)
-                       return i;
-       }
-
-       return NULL;
-}
-
-static void __unregister_enc_region_locked(struct kvm *kvm,
-                                          struct enc_region *region)
-{
-       sev_unpin_memory(kvm, region->pages, region->npages);
-       list_del(&region->list);
-       kfree(region);
+       return 0;
 }
 
 int svm_unregister_enc_region(struct kvm *kvm,
                              struct kvm_enc_region *range)
 {
-       struct enc_region *region;
-       int ret;
-
-       mutex_lock(&kvm->lock);
-
-       if (!sev_guest(kvm)) {
-               ret = -ENOTTY;
-               goto failed;
-       }
-
-       region = find_enc_region(kvm, range);
-       if (!region) {
-               ret = -EINVAL;
-               goto failed;
-       }
-
-       /*
-        * Ensure that all guest tagged cache entries are flushed before
-        * releasing the pages back to the system for use. CLFLUSH will
-        * not do this, so issue a WBINVD.
-        */
-       wbinvd_on_all_cpus();
-
-       __unregister_enc_region_locked(kvm, region);
-
-       mutex_unlock(&kvm->lock);
        return 0;
-
-failed:
-       mutex_unlock(&kvm->lock);
-       return ret;
 }
 
 void sev_vm_destroy(struct kvm *kvm)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct list_head *head = &sev->regions_list;
-       struct list_head *pos, *q;
        XA_STATE(xas, &sev->pages_xarray, 0);
        struct page *xa_page;
 
@@ -1196,17 +1092,6 @@ void sev_vm_destroy(struct kvm *kvm)
         */
        wbinvd_on_all_cpus();
 
-       /*
-        * if userspace was terminated before unregistering the memory regions
-        * then lets unpin all the registered memory.
-        */
-       if (!list_empty(head)) {
-               list_for_each_safe(pos, q, head) {
-                       __unregister_enc_region_locked(kvm,
-                               list_entry(pos, struct enc_region, list));
-               }
-       }
-
        /* Release each pinned page that SEV tracked in sev->pages_xarray. */
        xas_for_each(&xas, xa_page, ULONG_MAX) {
                put_page(xa_page);
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 278c46bc52aa..98d3d7b299cb 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -64,7 +64,6 @@ struct kvm_sev_info {
        unsigned int handle;    /* SEV firmware handle */
        int fd;                 /* SEV device fd */
        unsigned long pages_locked; /* Number of pages locked */
-       struct list_head regions_list;  /* List of registered regions */
        struct xarray pages_xarray; /* List of PFN locked */
 };
 
-- 
2.17.1