Subject: linux-next: manual merge of the kvm tree with Linus' tree

From: Stephen Rothwell <[email-masked]>
Date: Thu, 2 Apr 2020 13:36:37 +1100

Hi all,

Today's linux-next merge of the kvm tree got a conflict in:

  arch/x86/kvm/svm/svm.c

between commits:

  aaca21007ba1 ("KVM: SVM: Fix the svm vmexit code for WRMSR")
  2da1ed62d55c ("KVM: SVM: document KVM_MEM_ENCRYPT_OP, let userspace detect if SEV is available")
  2e2409afe5f0 ("KVM: SVM: Issue WBINVD after deactivating an SEV guest")

from Linus' tree and commits:

  83a2c705f002 ("kVM SVM: Move SVM related files to own sub-directory")
  41f08f0506c0 ("KVM: SVM: Move SEV code to separate file")

(at least)

from the kvm tree.

Its a bit of a pain this code movement appearing during the merge
window.  Is it really intended for v5.7?

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 621a36702636..2be5bbae3a40 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -34,6 +34,7 @@
 #include <asm/kvm_para.h>
 #include <asm/irq_remapping.h>
 #include <asm/spec-ctrl.h>
+#include <asm/cpu_device_id.h>
 
 #include <asm/virtext.h>
 #include "trace.h"
@@ -47,7 +48,7 @@ MODULE_LICENSE("GPL");
 
 #ifdef MODULE
 static const struct x86_cpu_id svm_cpu_id[] = {
-	X86_FEATURE_MATCH(X86_FEATURE_SVM),
+	X86_MATCH_FEATURE(X86_FEATURE_SVM, NULL),
 	{}
 };
 MODULE_DEVICE_TABLE(x86cpu, svm_cpu_id);
@@ -3715,7 +3716,8 @@ static void svm_handle_exit_irqoff(struct kvm_vcpu *vcpu,
 	enum exit_fastpath_completion *exit_fastpath)
 {
 	if (!is_guest_mode(vcpu) &&
-		to_svm(vcpu)->vmcb->control.exit_code == EXIT_REASON_MSR_WRITE)
+	    to_svm(vcpu)->vmcb->control.exit_code == SVM_EXIT_MSR &&
+	    to_svm(vcpu)->vmcb->control.exit_info_1)
 		*exit_fastpath = handle_fastpath_set_msr_irqoff(vcpu);
 }

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 3ef57dee48cc..0e3fc311d7da 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -920,6 +920,9 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
 	if (!svm_sev_enabled())
 		return -ENOTTY;
 
+	if (!argp)
+		return 0;
+
 	if (copy_from_user(&sev_cmd, argp, sizeof(struct kvm_sev_cmd)))
 		return -EFAULT;
 
@@ -1030,14 +1033,6 @@ find_enc_region(struct kvm *kvm, struct kvm_enc_region *range)
 static void __unregister_enc_region_locked(struct kvm *kvm,
 					   struct enc_region *region)
 {
-	/*
-	 * 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);
-
 	sev_unpin_memory(kvm, region->pages, region->npages);
 	list_del(&region->list);
 	kfree(region);
@@ -1062,6 +1057,13 @@ int svm_unregister_enc_region(struct kvm *kvm,
 		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);
@@ -1083,6 +1085,13 @@ void sev_vm_destroy(struct kvm *kvm)
 
 	mutex_lock(&kvm->lock);
 
+	/*
+	 * 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();
+
 	/*
 	 * if userspace was terminated before unregistering the memory regions
 	 * then lets unpin all the registered memory.
-- 
2.25.0

-- 
Cheers,
Stephen Rothwell