git: be14baa34b82 - stable/13 - vmm: don't free unallocated memory

The branch stable/13 has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=be14baa34b82e3ca50d0a2b61ddb05b355616c93

commit be14baa34b82e3ca50d0a2b61ddb05b355616c93
Author:     Corvin Köhne <corvink@FreeBSD.org>
AuthorDate: 2023-05-10 13:19:25 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2023-05-11 13:32:32 +0000

    vmm: don't free unallocated memory
    
    If vmx or svm is disabled in BIOS or the device isn't supported by vmm,
    modinit won't allocate these state save areas. As kmem_free panics when
    passing a NULL pointer to it, loading the vmm kernel module causes a
    panic too.
    
    PR:                     271251
    Reviewed by:            markj
    Fixes:                  74ac712f72cfd6d7b3db3c9d3b72ccf2824aa183 ("vmm: Dynamically allocate a couple of per-CPU state save areas")
    MFC after:              1 week
    Sponsored by:           Beckhoff Automation GmbH & Co. KG
    Differential Revision:  https://reviews.freebsd.org/D39974
    
    (cherry picked from commit b10e100d1696782cfebef09b5870dfc6d1b3217b)
---
 sys/amd64/vmm/amd/svm.c   | 5 ++++-
 sys/amd64/vmm/intel/vmx.c | 4 +++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/sys/amd64/vmm/amd/svm.c b/sys/amd64/vmm/amd/svm.c
index 0af7342128f2..d295401a9043 100644
--- a/sys/amd64/vmm/amd/svm.c
+++ b/sys/amd64/vmm/amd/svm.c
@@ -166,7 +166,10 @@ svm_modcleanup(void)
 {
 
 	smp_rendezvous(NULL, svm_disable, NULL, NULL);
-	kmem_free(hsave, (mp_maxid + 1) * PAGE_SIZE);
+
+	if (hsave != NULL)
+		kmem_free(hsave, (mp_maxid + 1) * PAGE_SIZE);
+
 	return (0);
 }
 
diff --git a/sys/amd64/vmm/intel/vmx.c b/sys/amd64/vmm/intel/vmx.c
index 55ed5fdf1a00..8b8f8fe6cb25 100644
--- a/sys/amd64/vmm/intel/vmx.c
+++ b/sys/amd64/vmm/intel/vmx.c
@@ -619,7 +619,9 @@ vmx_modcleanup(void)
 		nmi_flush_l1d_sw = 0;
 
 	smp_rendezvous(NULL, vmx_disable, NULL, NULL);
-	kmem_free(vmxon_region, (mp_maxid + 1) * PAGE_SIZE);
+
+	if (vmxon_region != NULL)
+		kmem_free(vmxon_region, (mp_maxid + 1) * PAGE_SIZE);
 
 	return (0);
 }