Re: [PATCH Part2 RFC v2 32/37] KVM: SVM: Add support to handle MSR based Page State Change VMGEXIT
From: Peter Gonda <hidden>
Date: 2021-05-10 17:36:01
Also in:
lkml
+static int snp_make_page_shared(struct kvm_vcpu *vcpu, gpa_t gpa, kvm_pfn_t pfn, int level)
+{
+ struct rmpupdate val;
+ int rc, rmp_level;
+ struct rmpentry *e;
+
+ e = snp_lookup_page_in_rmptable(pfn_to_page(pfn), &rmp_level);
+ if (!e)
+ return -EINVAL;
+
+ if (!rmpentry_assigned(e))
+ return 0;
+
+ /* Log if the entry is validated */
+ if (rmpentry_validated(e))
+ pr_debug_ratelimited("Remove RMP entry for a validated gpa 0x%llx\n", gpa);
+
+ /*
+ * Is the page part of an existing 2M RMP entry ? Split the 2MB into multiple
+ * of 4K-page before making the memory shared.
+ */
+ if ((level == PG_LEVEL_4K) && (rmp_level == PG_LEVEL_2M)) {
+ rc = snp_rmptable_psmash(vcpu, pfn);
+ if (rc)
+ return rc;
+ }
+
+ memset(&val, 0, sizeof(val));
+ val.pagesize = X86_TO_RMP_PG_LEVEL(level);This is slightly different from Rev 2.00 of the GHCB spec. This defaults to 2MB page sizes, when the spec says the only valid settings for level are 0 -> 4k pages or 1 -> 2MB pages. Should this enforce the same strictness as the spec?
+ return rmpupdate(pfn_to_page(pfn), &val);
+}
+
+static int snp_make_page_private(struct kvm_vcpu *vcpu, gpa_t gpa, kvm_pfn_t pfn, int level)
+{
+ struct kvm_sev_info *sev = &to_kvm_svm(vcpu->kvm)->sev_info;
+ struct rmpupdate val;
+ struct rmpentry *e;
+ int rmp_level;
+
+ e = snp_lookup_page_in_rmptable(pfn_to_page(pfn), &rmp_level);
+ if (!e)
+ return -EINVAL;
+
+ /* Log if the entry is validated */
+ if (rmpentry_validated(e))
+ pr_err_ratelimited("Asked to make a pre-validated gpa %llx private\n", gpa);
+
+ memset(&val, 0, sizeof(val));
+ val.gpa = gpa;
+ val.asid = sev->asid;
+ val.pagesize = X86_TO_RMP_PG_LEVEL(level);Same comment as above.
+ val.assigned = true; + + return rmpupdate(pfn_to_page(pfn), &val); +}