Add 2 small infrastructure functions here which to enable pinning the SEV
guest pages used for sev_launch_update_data() using sev_get_page().
Pin the memory for the data being passed to launch_update_data() because it
gets encrypted before the guest is first run and must not be moved which
would corrupt it.
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 | 57 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 57 insertions(+)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 8d56d1afb33e..4a0157254fef 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -454,6 +454,37 @@ static int sev_get_page(struct kvm *kvm, gfn_t gfn,
kvm_pfn_t pfn)
return 0;
}
+static struct kvm_memory_slot *hva_to_memslot(struct kvm *kvm,
+ unsigned long hva)
+{
+ struct kvm_memslots *slots = kvm_memslots(kvm);
+ struct kvm_memory_slot *memslot;
+
+ kvm_for_each_memslot(memslot, slots) {
+ if (hva >= memslot->userspace_addr &&
+ hva < memslot->userspace_addr +
+ (memslot->npages << PAGE_SHIFT))
+ return memslot;
+ }
+
+ return NULL;
+}
+
+static bool hva_to_gfn(struct kvm *kvm, unsigned long hva, gfn_t *gfn)
+{
+ struct kvm_memory_slot *memslot;
+ gpa_t gpa_offset;
+
+ memslot = hva_to_memslot(kvm, hva);
+ if (!memslot)
+ return false;
+
+ gpa_offset = hva - memslot->userspace_addr;
+ *gfn = ((memslot->base_gfn << PAGE_SHIFT) + gpa_offset) >> PAGE_SHIFT;
+
+ return true;
+}
+
static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
{
unsigned long vaddr, vaddr_end, next_vaddr, npages, pages, size, i;
@@ -462,6 +493,7 @@ static int sev_launch_update_data(struct kvm *kvm, struct
kvm_sev_cmd *argp)
struct sev_data_launch_update_data *data;
struct page **inpages;
int ret;
+ int srcu_idx;
if (!sev_guest(kvm))
return -ENOTTY;
@@ -484,6 +516,31 @@ static int sev_launch_update_data(struct kvm *kvm, struct
kvm_sev_cmd *argp)
goto e_free;
}
+ /*
+ * Increment the page ref count so that the pages do not get migrated or
+ * moved after we are done from the LAUNCH_UPDATE_DATA.
+ */
+
+ /* ensure hva_to_gfn translations remain valid */
+ srcu_idx = srcu_read_lock(&kvm->srcu);
+
+ for (i = 0; i < npages; i++) {
+ gfn_t gfn;
+
+ if (!hva_to_gfn(kvm, (vaddr + (i * PAGE_SIZE)) & PAGE_MASK,
&gfn)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ ret = sev_get_page(kvm, gfn, page_to_pfn(inpages[i]));
+ if (ret)
+ break;
+ }
+
+ srcu_read_unlock(&kvm->srcu, srcu_idx);
+ if (ret)
+ goto e_unpin;
+
/*
* The LAUNCH_UPDATE command will perform in-place encryption of the
* memory content (i.e it will write the same memory region with C=1).
--
2.17.1
