FAILED: patch "[PATCH] KVM: x86: Re-split x2APIC ICR into ICR+ICR2 for AMD (x2AVIC)" failed to apply to 6.1-stable tree

The patch below does not apply to the 6.1-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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 73b42dc69be8564d4951a14d00f827929fe5ef79
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2024100124-partly-overact-759b@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

73b42dc69be8 ("KVM: x86: Re-split x2APIC ICR into ICR+ICR2 for AMD (x2AVIC)") d33234342f8b ("KVM: x86: Move x2APIC ICR helper above kvm_apic_write_nodecode()") 71bf395a276f ("KVM: x86: Enforce x2APIC's must-be-zero reserved ICR bits") 4b7c3f6d04bd ("KVM: x86: Make x2APIC ID 100% readonly")
c7d4c5f01961 ("KVM: x86: Drop unused check_apicv_inhibit_reasons() callback definition") 5f18c642ff7e ("KVM: VMX: Move out vmx_x86_ops to 'main.c' to dispatch VMX and TDX") 0ec3d6d1f169 ("KVM: x86: Fully defer to vendor code to decide how to force immediate exit") bf1a49436ea3 ("KVM: x86: Move handling of is_guest_mode() into fastpath exit handlers") 11776aa0cfa7 ("KVM: VMX: Handle forced exit due to preemption timer in fastpath") e6b5d16bbd2d ("KVM: VMX: Re-enter guest in fastpath for "spurious" preemption timer exits") 9c9025ea003a ("KVM: x86: Plumb "force_immediate_exit" into kvm_entry() tracepoint") 8ecb10bcbfa3 ("Merge tag 'kvm-x86-lam-6.8' of https://github.com/kvm-x86/linux into HEAD")

thanks,

greg k-h

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

From 73b42dc69be8564d4951a14d00f827929fe5ef79 Mon Sep 17 00:00:00 2001
From: Sean Christopherson <[email protected]>
Date: Fri, 19 Jul 2024 16:51:00 -0700
Subject: [PATCH] KVM: x86: Re-split x2APIC ICR into ICR+ICR2 for AMD (x2AVIC)

Re-introduce the "split" x2APIC ICR storage that KVM used prior to Intel's IPI virtualization support, but only for AMD. While not stated anywhere in the APM, despite stating the ICR is a single 64-bit register, AMD CPUs store the 64-bit ICR as two separate 32-bit values in ICR and ICR2. When IPI virtualization (IPIv on Intel, all AVIC flavors on AMD) is enabled, KVM needs to match CPU behavior as some ICR ICR writes will be handled by the CPU, not by KVM.

Add a kvm_x86_ops knob to control the underlying format used by the CPU to store the x2APIC ICR, and tune it to AMD vs. Intel regardless of whether or not x2AVIC is enabled. If KVM is handling all ICR writes, the storage format for x2APIC mode doesn't matter, and having the behavior follow AMD versus Intel will provide better test coverage and ease debugging.

index 95396e4cb3da..f9dfb2d62053 100644
@@ -1727,6 +1727,8 @@ struct kvm_x86_ops {
 	void (*enable_nmi_window)(struct kvm_vcpu *vcpu);
 	void (*enable_irq_window)(struct kvm_vcpu *vcpu);
 	void (*update_cr8_intercept)(struct kvm_vcpu *vcpu, int tpr, int irr);
+
+	const bool x2apic_icr_is_split;
 	const unsigned long required_apicv_inhibits;
 	bool allow_apicv_in_x2apic_without_x2apic_virtualization;
 	void (*refresh_apicv_exec_ctrl)(struct kvm_vcpu *vcpu);

index d8cfe8f23327..eb3de01602b9 100644
@@ -5053,6 +5053,8 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
 	.enable_nmi_window = svm_enable_nmi_window,
 	.enable_irq_window = svm_enable_irq_window,
 	.update_cr8_intercept = svm_update_cr8_intercept,
+
+	.x2apic_icr_is_split = true,
 	.set_virtual_apic_mode = avic_refresh_virtual_apic_mode,
 	.refresh_apicv_exec_ctrl = avic_refresh_apicv_exec_ctrl,
 	.apicv_post_state_restore = avic_apicv_post_state_restore,

index 4f6023a0deb3..0a094ebad4b1 100644
@@ -89,6 +89,8 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
 	.enable_nmi_window = vmx_enable_nmi_window,
 	.enable_irq_window = vmx_enable_irq_window,
 	.update_cr8_intercept = vmx_update_cr8_intercept,
+
+	.x2apic_icr_is_split = false,
 	.set_virtual_apic_mode = vmx_set_virtual_apic_mode,
 	.set_apic_access_page_addr = vmx_set_apic_access_page_addr,
 	.refresh_apicv_exec_ctrl = vmx_refresh_apicv_exec_ctrl,