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linux/debian/patches/patchset-pf/fixes/0043-KVM-VMX-Flush-shadow-VMCS-on-emergency-reboot.patch
2025-06-19 18:06:35 +03:00

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From d74cb6c8b70d9b5ad8482f4821679b83bad9de63 Mon Sep 17 00:00:00 2001
From: Chao Gao <chao.gao@intel.com>
Date: Mon, 24 Mar 2025 22:08:48 +0800
Subject: 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.
Fixes: 16f5b9034b69 ("KVM: nVMX: Copy processor-specific shadow-vmcs to VMCS12")
Cc: stable@vger.kernel.org
Signed-off-by: Chao Gao <chao.gao@intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20250324140849.2099723-1-chao.gao@intel.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/vmx/vmx.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -769,8 +769,11 @@ void vmx_emergency_disable_virtualizatio
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();
}