From baeb4de7ad12b700a91f2a7be8e1c0389a5c8fd4 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 21 Jul 2023 13:18:44 -0700 Subject: [PATCH] x86/reboot: KVM: Disable SVM during reboot via virt/KVM reboot callback Use the virt callback to disable SVM (and set GIF=1) during an emergency instead of blindly attempting to disable SVM. Like the VMX case, if a hypervisor, i.e. KVM, isn't loaded/active, SVM can't be in use. Acked-by: Kai Huang Link: https://lore.kernel.org/r/20230721201859.2307736-5-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/include/asm/virtext.h | 8 -------- arch/x86/kernel/reboot.c | 3 --- arch/x86/kvm/svm/svm.c | 19 +++++++++++++++++-- 3 files changed, 17 insertions(+), 13 deletions(-) diff --git a/arch/x86/include/asm/virtext.h b/arch/x86/include/asm/virtext.h index 5bc29fa..aaed662 100644 --- a/arch/x86/include/asm/virtext.h +++ b/arch/x86/include/asm/virtext.h @@ -133,12 +133,4 @@ fault: } } -/** Makes sure SVM is disabled, if it is supported on the CPU - */ -static inline void cpu_emergency_svm_disable(void) -{ - if (cpu_has_svm(NULL)) - cpu_svm_disable(); -} - #endif /* _ASM_X86_VIRTEX_H */ diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c index d2d0f26..48ad2d1 100644 --- a/arch/x86/kernel/reboot.c +++ b/arch/x86/kernel/reboot.c @@ -826,9 +826,6 @@ void cpu_emergency_disable_virtualization(void) if (callback) callback(); rcu_read_unlock(); - - /* KVM_AMD doesn't yet utilize the common callback. */ - cpu_emergency_svm_disable(); } #if defined(CONFIG_SMP) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index d381ad4..1ae9c2c 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -39,6 +39,7 @@ #include #include #include +#include #include #include @@ -563,6 +564,11 @@ out: preempt_enable(); } +static void svm_emergency_disable(void) +{ + cpu_svm_disable(); +} + static void svm_hardware_disable(void) { /* Make sure we clean up behind us */ @@ -5209,6 +5215,13 @@ static struct kvm_x86_init_ops svm_init_ops __initdata = { .pmu_ops = &amd_pmu_ops, }; +static void __svm_exit(void) +{ + kvm_x86_vendor_exit(); + + cpu_emergency_unregister_virt_callback(svm_emergency_disable); +} + static int __init svm_init(void) { int r; @@ -5222,6 +5235,8 @@ static int __init svm_init(void) if (r) return r; + cpu_emergency_register_virt_callback(svm_emergency_disable); + /* * Common KVM initialization _must_ come last, after this, /dev/kvm is * exposed to userspace! @@ -5234,14 +5249,14 @@ static int __init svm_init(void) return 0; err_kvm_init: - kvm_x86_vendor_exit(); + __svm_exit(); return r; } static void __exit svm_exit(void) { kvm_exit(); - kvm_x86_vendor_exit(); + __svm_exit(); } module_init(svm_init) -- 2.7.4