FAILED: patch "[PATCH] KVM: VMX: Preserve negative return value in vmx_handle_exit()" failed to apply to 5.10-stable tree

FAILED: patch "[PATCH] KVM: VMX: Preserve negative return value in vmx_handle_exit()" failed to apply to 5.10-stable tree

[gregkh]

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 <stable@vger.kernel.org>.

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 cef48693da1e964e9f192bfc16cd0ed287c48337
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026110401-siren-occupancy-2a61@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

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

From cef48693da1e964e9f192bfc16cd0ed287c48337 Mon Sep 17 00:00:00 2001
From: Xiaoyao Li <xiaoyao.li@intel.com>
Date: Wed, 19 Aug 2026 17:49:00 +0800
Subject: [PATCH] KVM: VMX: Preserve negative return value in vmx_handle_exit()
 with bus lock detected

Preserve the negative return value from __vmx_handle_exit() when a bus
lock is detected, instead of always overwriting it with 0.

The purpose of bus_lock_detected handling is to force a userspace exit to
inform userspace that a bus lock happened. The negative return value can
achieve this purpose, and changing the negative value to 0 fails to return
an error to userspace. So, preserve the negative return value.

Fixes: fe6b6bc802b4 ("KVM: VMX: Enable bus lock VM exit")
Cc: stable@vger.kernel.org
Reported-by: sashiko-bot@kernel.org
Closes: https://lore.kernel.org/all/20260805034602.5B2BB1F000E9@smtp.kernel.org/
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://patch.msgid.link/20260819094903.3060020-7-xiaoyao.li@intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 965141e0d4c8..6df390ae8708 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6864,11 +6864,12 @@ int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
 	 * a bus lock in guest.
 	 */
 	if (vmx_get_exit_reason(vcpu).bus_lock_detected) {
-		if (ret > 0)
+		if (ret > 0) {
 			vcpu->run->exit_reason = KVM_EXIT_X86_BUS_LOCK;
+			ret = 0;
+		}
 
 		vcpu->run->flags |= KVM_RUN_X86_BUS_LOCK;
-		return 0;
 	}
 	return ret;
 }

Re: FAILED: patch "[PATCH] KVM: VMX: Preserve negative return value in vmx_handle_exit()" failed to apply to 5.10-stable tree

[Xiaoyao Li]

On 11/5/2026 3:19 AM, gregkh@linuxfoundation.org wrote:
> 
> 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 <stable@vger.kernel.org>.

This one doesn't need to be backported to 5.10-stable. It fixes fe6b6bc802b4
("KVM: VMX: Enable bus lock VM exit"), which was merged since 5.12

> 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 cef48693da1e964e9f192bfc16cd0ed287c48337
> # <resolve conflicts, build, test, etc.>
> git commit -s
> git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026110401-siren-occupancy-2a61@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..'
> 
> Possible dependencies:
> 
> 
> 
> thanks,
> 
> greg k-h
> 
> ------------------ original commit in Linus's tree ------------------
> 
> From cef48693da1e964e9f192bfc16cd0ed287c48337 Mon Sep 17 00:00:00 2001
> From: Xiaoyao Li <xiaoyao.li@intel.com>
> Date: Wed, 19 Aug 2026 17:49:00 +0800
> Subject: [PATCH] KVM: VMX: Preserve negative return value in vmx_handle_exit()
>  with bus lock detected
> 
> Preserve the negative return value from __vmx_handle_exit() when a bus
> lock is detected, instead of always overwriting it with 0.
> 
> The purpose of bus_lock_detected handling is to force a userspace exit to
> inform userspace that a bus lock happened. The negative return value can
> achieve this purpose, and changing the negative value to 0 fails to return
> an error to userspace. So, preserve the negative return value.
> 
> Fixes: fe6b6bc802b4 ("KVM: VMX: Enable bus lock VM exit")
> Cc: stable@vger.kernel.org
> Reported-by: sashiko-bot@kernel.org
> Closes: https://lore.kernel.org/all/20260805034602.5B2BB1F000E9@smtp.kernel.org/
> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
> Link: https://patch.msgid.link/20260819094903.3060020-7-xiaoyao.li@intel.com
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> 
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 965141e0d4c8..6df390ae8708 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -6864,11 +6864,12 @@ int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
>  	 * a bus lock in guest.
>  	 */
>  	if (vmx_get_exit_reason(vcpu).bus_lock_detected) {
> -		if (ret > 0)
> +		if (ret > 0) {
>  			vcpu->run->exit_reason = KVM_EXIT_X86_BUS_LOCK;
> +			ret = 0;
> +		}
>  
>  		vcpu->run->flags |= KVM_RUN_X86_BUS_LOCK;
> -		return 0;
>  	}
>  	return ret;
>  }