FAILED: patch "[PATCH] KVM: VMX: Flush shadow VMCS on emergency reboot" failed to apply to 5.10-stable tree

The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x a0ee1d5faff135e28810f29e0f06328c66f89852
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025062040-probe-earthen-bc3c@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From a0ee1d5faff135e28810f29e0f06328c66f89852 Mon Sep 17 00:00:00 2001
From: Chao Gao <[email protected]>
Date: Mon, 24 Mar 2025 22:08:48 +0800
Subject: [PATCH] KVM: VMX: Flush shadow VMCS on emergency reboot

Ensure the shadow VMCS cache is evicted during an emergency reboot to prevent potential memory corruption if the cache is evicted after reboot.

This issue was identified through code inspection, as __loaded_vmcs_clear() flushes both the normal VMCS and the shadow VMCS.

Avoid checking the "launched" state during an emergency reboot, unlike the behavior in __loaded_vmcs_clear(). This is important because reboot NMIs can interfere with operations like copy_shadow_to_vmcs12(), where shadow VMCSes are loaded directly using VMPTRLD. In such cases, if NMIs occur right after the VMCS load, the shadow VMCSes will be active but the "launched" state may not be set.

index ef2d7208dd20..848c4963bdb8 100644
@@ -770,8 +770,11 @@ void vmx_emergency_disable_virtualization_cpu(void)
 		return;
 
 	list_for_each_entry(v, &per_cpu(loaded_vmcss_on_cpu, cpu),
-			    loaded_vmcss_on_cpu_link)
+			    loaded_vmcss_on_cpu_link) {
 		vmcs_clear(v->vmcs);
+		if (v->shadow_vmcs)
+			vmcs_clear(v->shadow_vmcs);
+	}
 
 	kvm_cpu_vmxoff();
 }