[PATCH 5.10 599/717] KVM: SVM: Remove the call to sev_platform_status() during setup

Greg Kroah-Hartman
2020-12-28T14:28:18Z

From: Tom Lendacky <thomas.lendacky@amd.com>

commit 9d4747d02376aeb8de38afa25430de79129c5799 upstream.

When both KVM support and the CCP driver are built into the kernel instead
of as modules, KVM initialization can happen before CCP initialization. As
a result, sev_platform_status() will return a failure when it is called
from sev_hardware_setup(), when this isn't really an error condition.

Since sev_platform_status() doesn't need to be called at this time anyway,
remove the invocation from sev_hardware_setup().

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Message-Id: <618380488358b56af558f2682203786f09a49483.1607620209.git.thomas.lendacky@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/x86/kvm/svm/sev.c | 22 +---------------------
1 file changed, 1 insertion(+), 21 deletions(-)

--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1127,9 +1127,6 @@ void sev_vm_destroy(struct kvm *kvm)

int __init sev_hardware_setup(void)
{
- struct sev_user_data_status *status;
- int rc;
-
/* Maximum number of encrypted guests supported simultaneously */
max_sev_asid = cpuid_ecx(0x8000001F);

@@ -1148,26 +1145,9 @@ int __init sev_hardware_setup(void)
if (!sev_reclaim_asid_bitmap)
return 1;

- status = kmalloc(sizeof(*status), GFP_KERNEL);
- if (!status)
- return 1;
-
- /*
- * Check SEV platform status.
- *
- * PLATFORM_STATUS can be called in any state, if we failed to query
- * the PLATFORM status then either PSP firmware does not support SEV
- * feature or SEV firmware is dead.
- */
- rc = sev_platform_status(status, NULL);
- if (rc)
- goto err;
-
pr_info("SEV supported\n");

-err:
- kfree(status);
- return rc;
+ return 0;
}

void sev_hardware_teardown(void)