Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'hyperv-fixes-signed-20230402' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv fixes from Wei Liu:
- Fix a bug in channel allocation for VMbus (Mohammed Gamal)
- Do not allow root partition functionality in CVM (Michael Kelley)
* tag 'hyperv-fixes-signed-20230402' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
x86/hyperv: Block root partition functionality in a Confidential VM
Drivers: vmbus: Check for channel allocation before looking up relids
+12
-4
+8
-4
arch/x86/kernel/cpu/mshyperv.c
+8
-4
arch/x86/kernel/cpu/mshyperv.c
···
358
358
* To mirror what Windows does we should extract CPU management
359
359
* features and use the ReservedIdentityBit to detect if Linux is the
360
360
* root partition. But that requires negotiating CPU management
361
-
* interface (a process to be finalized).
361
+
* interface (a process to be finalized). For now, use the privilege
362
+
* flag as the indicator for running as root.
362
363
*
363
-
* For now, use the privilege flag as the indicator for running as
364
-
* root.
364
+
* Hyper-V should never specify running as root and as a Confidential
365
+
* VM. But to protect against a compromised/malicious Hyper-V trying
366
+
* to exploit root behavior to expose Confidential VM memory, ignore
367
+
* the root partition setting if also a Confidential VM.
365
368
*/
366
-
if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_CPU_MANAGEMENT) {
369
+
if ((ms_hyperv.priv_high & HV_CPU_MANAGEMENT) &&
370
+
!(ms_hyperv.priv_high & HV_ISOLATION)) {
367
371
hv_root_partition = true;
368
372
pr_info("Hyper-V: running as root partition\n");
369
373
}
+4
drivers/hv/connection.c
+4
drivers/hv/connection.c
···
409
409
*/
410
410
struct vmbus_channel *relid2channel(u32 relid)
411
411
{
412
+
if (vmbus_connection.channels == NULL) {
413
+
pr_warn_once("relid2channel: relid=%d: No channels mapped!\n", relid);
414
+
return NULL;
415
+
}
412
416
if (WARN_ON(relid >= MAX_CHANNEL_RELIDS))
413
417
return NULL;
414
418
return READ_ONCE(vmbus_connection.channels[relid]);