linux-kernel - [RFC PATCH 05/11] KVM: x86: Refactor sev's flag migration_in

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Date:   Mon,  7 Aug 2023 23:01:08 +0000
From:   Ackerley Tng <ackerleytng@...gle.com>
To:     pbonzini@...hat.com, seanjc@...gle.com, tglx@...utronix.de,
        x86@...nel.org, kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-kselftest@...r.kernel.org
Cc:     mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com,
        hpa@...or.com, shuah@...nel.org, andrew.jones@...ux.dev,
        ricarkol@...gle.com, chao.p.peng@...ux.intel.com, tabba@...gle.com,
        jarkko@...nel.org, yu.c.zhang@...ux.intel.com,
        vannapurve@...gle.com, ackerleytng@...gle.com,
        erdemaktas@...gle.com, mail@...iej.szmigiero.name, vbabka@...e.cz,
        david@...hat.com, qperret@...gle.com, michael.roth@....com,
        wei.w.wang@...el.com, liam.merwick@...cle.com,
        isaku.yamahata@...il.com, kirill.shutemov@...ux.intel.com,
        Sagi Shahar <sagis@...gle.com>
Subject: [RFC PATCH 05/11] KVM: x86: Refactor sev's flag migration_in_progress
 to kvm struct

The migration_in_progress flag will also be needed for migration of
non-sev VMs.

Co-developed-by: Sagi Shahar <sagis@...gle.com>
Signed-off-by: Sagi Shahar <sagis@...gle.com>
Co-developed-by: Vishal Annapurve <vannapurve@...gle.com>
Signed-off-by: Vishal Annapurve <vannapurve@...gle.com>
Signed-off-by: Ackerley Tng <ackerleytng@...gle.com>
---
 arch/x86/kvm/svm/sev.c   | 17 ++++++-----------
 arch/x86/kvm/svm/svm.h   |  1 -
 include/linux/kvm_host.h |  1 +
 3 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 07756b7348ae..725289b523c7 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1556,8 +1556,6 @@ static bool is_cmd_allowed_from_mirror(u32 cmd_id)
 
 static int sev_lock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm)
 {
-	struct kvm_sev_info *dst_sev = &to_kvm_svm(dst_kvm)->sev_info;
-	struct kvm_sev_info *src_sev = &to_kvm_svm(src_kvm)->sev_info;
 	int r = -EBUSY;
 
 	if (dst_kvm == src_kvm)
@@ -1567,10 +1565,10 @@ static int sev_lock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm)
 	 * Bail if these VMs are already involved in a migration to avoid
 	 * deadlock between two VMs trying to migrate to/from each other.
 	 */
-	if (atomic_cmpxchg_acquire(&dst_sev->migration_in_progress, 0, 1))
+	if (atomic_cmpxchg_acquire(&dst_kvm->migration_in_progress, 0, 1))
 		return -EBUSY;
 
-	if (atomic_cmpxchg_acquire(&src_sev->migration_in_progress, 0, 1))
+	if (atomic_cmpxchg_acquire(&src_kvm->migration_in_progress, 0, 1))
 		goto release_dst;
 
 	r = -EINTR;
@@ -1583,21 +1581,18 @@ static int sev_lock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm)
 unlock_dst:
 	mutex_unlock(&dst_kvm->lock);
 release_src:
-	atomic_set_release(&src_sev->migration_in_progress, 0);
+	atomic_set_release(&src_kvm->migration_in_progress, 0);
 release_dst:
-	atomic_set_release(&dst_sev->migration_in_progress, 0);
+	atomic_set_release(&dst_kvm->migration_in_progress, 0);
 	return r;
 }
 
 static void sev_unlock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm)
 {
-	struct kvm_sev_info *dst_sev = &to_kvm_svm(dst_kvm)->sev_info;
-	struct kvm_sev_info *src_sev = &to_kvm_svm(src_kvm)->sev_info;
-
 	mutex_unlock(&dst_kvm->lock);
 	mutex_unlock(&src_kvm->lock);
-	atomic_set_release(&dst_sev->migration_in_progress, 0);
-	atomic_set_release(&src_sev->migration_in_progress, 0);
+	atomic_set_release(&dst_kvm->migration_in_progress, 0);
+	atomic_set_release(&src_kvm->migration_in_progress, 0);
 }
 
 /* vCPU mutex subclasses.  */
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 18af7e712a5a..d306e2312b53 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -87,7 +87,6 @@ struct kvm_sev_info {
 	struct list_head mirror_vms; /* List of VMs mirroring */
 	struct list_head mirror_entry; /* Use as a list entry of mirrors */
 	struct misc_cg *misc_cg; /* For misc cgroup accounting */
-	atomic_t migration_in_progress;
 };
 
 struct kvm_svm {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 091bc89ae805..3e03eeca279f 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -842,6 +842,7 @@ struct kvm {
 #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
 	struct xarray mem_attr_array;
 #endif
+	atomic_t migration_in_progress;
 	char stats_id[KVM_STATS_NAME_SIZE];
 };
 
-- 
2.41.0.640.ga95def55d0-goog