migration: close kvm after cpr

cpr-transfer breaks vfio network connectivity to and from the guest, and
the host system log shows:
  irq bypass consumer (token 00000000a03c32e5) registration fails: -16
which is EBUSY.  This occurs because KVM descriptors are still open in
the old QEMU process.  Close them.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/qemu-devel/1751493538-202042-4-git-send-email-steven.sistare@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index d095d1b98f..8141854617 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -515,16 +515,23 @@ static int do_kvm_destroy_vcpu(CPUState *cpu)
         goto err;
     }
 
+    /* If I am the CPU that created coalesced_mmio_ring, then discard it */
+    if (s->coalesced_mmio_ring == (void *)cpu->kvm_run + PAGE_SIZE) {
+        s->coalesced_mmio_ring = NULL;
+    }
+
     ret = munmap(cpu->kvm_run, mmap_size);
     if (ret < 0) {
         goto err;
     }
+    cpu->kvm_run = NULL;
 
     if (cpu->kvm_dirty_gfns) {
         ret = munmap(cpu->kvm_dirty_gfns, s->kvm_dirty_ring_bytes);
         if (ret < 0) {
             goto err;
         }
+        cpu->kvm_dirty_gfns = NULL;
     }
 
     kvm_park_vcpu(cpu);
@@ -608,6 +615,31 @@ err:
     return ret;
 }
 
+void kvm_close(void)
+{
+    CPUState *cpu;
+
+    if (!kvm_state || kvm_state->fd == -1) {
+        return;
+    }
+
+    CPU_FOREACH(cpu) {
+        cpu_remove_sync(cpu);
+        close(cpu->kvm_fd);
+        cpu->kvm_fd = -1;
+        close(cpu->kvm_vcpu_stats_fd);
+        cpu->kvm_vcpu_stats_fd = -1;
+    }
+
+    if (kvm_state && kvm_state->fd != -1) {
+        close(kvm_state->vmfd);
+        kvm_state->vmfd = -1;
+        close(kvm_state->fd);
+        kvm_state->fd = -1;
+    }
+    kvm_state = NULL;
+}
+
 /*
  * dirty pages logging control
  */