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From: <gregkh@linuxfoundation.org>
To: seanjc@google.com, pbonzini@redhat.com, vkuznets@redhat.com
Cc: <stable@vger.kernel.org>
Subject: FAILED: patch "[PATCH] KVM: nVMX: Don't propagate vmcs12's PERF_GLOBAL_CTRL settings" failed to apply to 5.10-stable tree
Date: Sun, 16 Oct 2022 17:47:27 +0200	[thread overview]
Message-ID: <1665935247137223@kroah.com> (raw)


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>.

Possible dependencies:

def9d705c05e ("KVM: nVMX: Don't propagate vmcs12's PERF_GLOBAL_CTRL settings to vmcs02")
389ab25216c9 ("KVM: nVMX: Pull KVM L0's desired controls directly from vmcs01")
d041b5ea9335 ("KVM: nVMX: Enable nested TSC scaling")

thanks,

greg k-h

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

From def9d705c05eab3fdedeb10ad67907513b12038e Mon Sep 17 00:00:00 2001
From: Sean Christopherson <seanjc@google.com>
Date: Tue, 30 Aug 2022 15:37:21 +0200
Subject: [PATCH] KVM: nVMX: Don't propagate vmcs12's PERF_GLOBAL_CTRL settings
 to vmcs02

Don't propagate vmcs12's VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL to vmcs02.
KVM doesn't disallow L1 from using VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL
even when KVM itself doesn't use the control, e.g. due to the various
CPU errata that where the MSR can be corrupted on VM-Exit.

Preserve KVM's (vmcs01) setting to hopefully avoid having to toggle the
bit in vmcs02 at a later point.  E.g. if KVM is loading PERF_GLOBAL_CTRL
when running L1, then odds are good KVM will also load the MSR when
running L2.

Fixes: 8bf00a529967 ("KVM: VMX: add support for switching of PERF_GLOBAL_CTRL")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20220830133737.1539624-18-vkuznets@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 1743319015b7..400e015afa64 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2359,9 +2359,14 @@ static void prepare_vmcs02_early(struct vcpu_vmx *vmx, struct loaded_vmcs *vmcs0
 	 * are emulated by vmx_set_efer() in prepare_vmcs02(), but speculate
 	 * on the related bits (if supported by the CPU) in the hope that
 	 * we can avoid VMWrites during vmx_set_efer().
+	 *
+	 * Similarly, take vmcs01's PERF_GLOBAL_CTRL in the hope that if KVM is
+	 * loading PERF_GLOBAL_CTRL via the VMCS for L1, then KVM will want to
+	 * do the same for L2.
 	 */
 	exec_control = __vm_entry_controls_get(vmcs01);
-	exec_control |= vmcs12->vm_entry_controls;
+	exec_control |= (vmcs12->vm_entry_controls &
+			 ~VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL);
 	exec_control &= ~(VM_ENTRY_IA32E_MODE | VM_ENTRY_LOAD_IA32_EFER);
 	if (cpu_has_load_ia32_efer()) {
 		if (guest_efer & EFER_LMA)


                 reply	other threads:[~2022-10-16 15:46 UTC|newest]

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