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Diffstat (limited to 'arch/x86/kvm/svm/sev.c')
-rw-r--r--arch/x86/kvm/svm/sev.c67
1 files changed, 32 insertions, 35 deletions
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 537aaddc852f..0ad70c12c7c3 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2226,51 +2226,47 @@ int sev_cpu_init(struct svm_cpu_data *sd)
* Pages used by hardware to hold guest encrypted state must be flushed before
* returning them to the system.
*/
-static void sev_flush_guest_memory(struct vcpu_svm *svm, void *va,
- unsigned long len)
+static void sev_flush_encrypted_page(struct kvm_vcpu *vcpu, void *va)
{
+ int asid = to_kvm_svm(vcpu->kvm)->sev_info.asid;
+
/*
- * If hardware enforced cache coherency for encrypted mappings of the
- * same physical page is supported, nothing to do.
+ * Note! The address must be a kernel address, as regular page walk
+ * checks are performed by VM_PAGE_FLUSH, i.e. operating on a user
+ * address is non-deterministic and unsafe. This function deliberately
+ * takes a pointer to deter passing in a user address.
*/
- if (boot_cpu_has(X86_FEATURE_SME_COHERENT))
- return;
+ unsigned long addr = (unsigned long)va;
/*
- * If the VM Page Flush MSR is supported, use it to flush the page
- * (using the page virtual address and the guest ASID).
+ * If CPU enforced cache coherency for encrypted mappings of the
+ * same physical page is supported, use CLFLUSHOPT instead. NOTE: cache
+ * flush is still needed in order to work properly with DMA devices.
*/
- if (boot_cpu_has(X86_FEATURE_VM_PAGE_FLUSH)) {
- struct kvm_sev_info *sev;
- unsigned long va_start;
- u64 start, stop;
-
- /* Align start and stop to page boundaries. */
- va_start = (unsigned long)va;
- start = (u64)va_start & PAGE_MASK;
- stop = PAGE_ALIGN((u64)va_start + len);
-
- if (start < stop) {
- sev = &to_kvm_svm(svm->vcpu.kvm)->sev_info;
+ if (boot_cpu_has(X86_FEATURE_SME_COHERENT)) {
+ clflush_cache_range(va, PAGE_SIZE);
+ return;
+ }
- while (start < stop) {
- wrmsrl(MSR_AMD64_VM_PAGE_FLUSH,
- start | sev->asid);
+ /*
+ * VM Page Flush takes a host virtual address and a guest ASID. Fall
+ * back to WBINVD if this faults so as not to make any problems worse
+ * by leaving stale encrypted data in the cache.
+ */
+ if (WARN_ON_ONCE(wrmsrl_safe(MSR_AMD64_VM_PAGE_FLUSH, addr | asid)))
+ goto do_wbinvd;
- start += PAGE_SIZE;
- }
+ return;
- return;
- }
+do_wbinvd:
+ wbinvd_on_all_cpus();
+}
- WARN(1, "Address overflow, using WBINVD\n");
- }
+void sev_guest_memory_reclaimed(struct kvm *kvm)
+{
+ if (!sev_guest(kvm))
+ return;
- /*
- * Hardware should always have one of the above features,
- * but if not, use WBINVD and issue a warning.
- */
- WARN_ONCE(1, "Using WBINVD to flush guest memory\n");
wbinvd_on_all_cpus();
}
@@ -2284,7 +2280,8 @@ void sev_free_vcpu(struct kvm_vcpu *vcpu)
svm = to_svm(vcpu);
if (vcpu->arch.guest_state_protected)
- sev_flush_guest_memory(svm, svm->sev_es.vmsa, PAGE_SIZE);
+ sev_flush_encrypted_page(vcpu, svm->sev_es.vmsa);
+
__free_page(virt_to_page(svm->sev_es.vmsa));
if (svm->sev_es.ghcb_sa_free)