[PATCH Part2 RFC v4 25/40] KVM: SVM: Reclaim the guest pages when SEV-SNP VM terminates
From: Brijesh Singh <hidden>
Date: 2021-07-07 18:38:46
Also in:
kvm, linux-crypto, linux-efi, linux-mm, lkml, platform-driver-x86
Subsystem:
kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
The guest pages of the SEV-SNP VM maybe added as a private page in the RMP entry (assigned bit is set). The guest private pages must be transitioned to the hypervisor state before its freed. Signed-off-by: Brijesh Singh <redacted> --- arch/x86/kvm/svm/sev.c | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 1f0635ac9ff9..4468995dd209 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c@@ -1940,6 +1940,45 @@ find_enc_region(struct kvm *kvm, struct kvm_enc_region *range) static void __unregister_enc_region_locked(struct kvm *kvm, struct enc_region *region) { + struct rmpupdate val = {}; + unsigned long i, pfn; + struct rmpentry *e; + int level, rc; + + /* + * The guest memory pages are assigned in the RMP table. Unassign it + * before releasing the memory. + */ + if (sev_snp_guest(kvm)) { + for (i = 0; i < region->npages; i++) { + pfn = page_to_pfn(region->pages[i]); + + if (need_resched()) + schedule(); + + e = snp_lookup_page_in_rmptable(region->pages[i], &level); + if (unlikely(!e)) + continue; + + /* If its not a guest assigned page then skip it. */ + if (!rmpentry_assigned(e)) + continue; + + /* Is the page part of a 2MB RMP entry? */ + if (level == PG_LEVEL_2M) { + val.pagesize = RMP_PG_SIZE_2M; + pfn &= ~(KVM_PAGES_PER_HPAGE(PG_LEVEL_2M) - 1); + } else { + val.pagesize = RMP_PG_SIZE_4K; + } + + /* Transition the page to hypervisor owned. */ + rc = rmpupdate(pfn_to_page(pfn), &val); + if (rc) + pr_err("Failed to release pfn 0x%lx ret=%d\n", pfn, rc); + } + } + sev_unpin_memory(kvm, region->pages, region->npages); list_del(®ion->list); kfree(region);
--
2.17.1