vmm_exclusive=0 leads to KVM setting X86_CR4_VMXE always and calling VMXON only when the vcpu is loaded. X86_CR4_VMXE is used as an indication in cpu_emergency_vmxoff() (called on kdump) if VMXOFF has to be called. This is obviously not the case if both are used independtly. Calling VMXOFF without a previous VMXON will result in an exception.
In addition, X86_CR4_VMXE is used as a mean to test if VMX is already in use by another VMM in hardware_enable(). So there can't really be co-existance. If the other VMM is prepared for co-existance and does a similar check, only one VMM can exist. If the other VMM is not prepared and blindly sets/clears X86_CR4_VMXE, we will get inconsistencies with X86_CR4_VMXE. As we also had bug reports related to clearing of vmcs with vmm_exclusive=0 this seems to be pretty much untested. So let's better drop it. While at it, directly move setting/clearing X86_CR4_VMXE into kvm_cpu_vmxon/off. Signed-off-by: David Hildenbrand <[email protected]> --- arch/x86/kvm/vmx.c | 38 +++++++------------------------------- 1 file changed, 7 insertions(+), 31 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 283aa86..bbbfe12 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -84,9 +84,6 @@ module_param_named(eptad, enable_ept_ad_bits, bool, S_IRUGO); static bool __read_mostly emulate_invalid_guest_state = true; module_param(emulate_invalid_guest_state, bool, S_IRUGO); -static bool __read_mostly vmm_exclusive = 1; -module_param(vmm_exclusive, bool, S_IRUGO); - static bool __read_mostly fasteoi = 1; module_param(fasteoi, bool, S_IRUGO); @@ -914,8 +911,6 @@ static void nested_release_page_clean(struct page *page) static unsigned long nested_ept_get_cr3(struct kvm_vcpu *vcpu); static u64 construct_eptp(unsigned long root_hpa); -static void kvm_cpu_vmxon(u64 addr); -static void kvm_cpu_vmxoff(void); static bool vmx_xsaves_supported(void); static int vmx_set_tss_addr(struct kvm *kvm, unsigned int addr); static void vmx_set_segment(struct kvm_vcpu *vcpu, @@ -2235,15 +2230,10 @@ static void decache_tsc_multiplier(struct vcpu_vmx *vmx) static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); - u64 phys_addr = __pa(per_cpu(vmxarea, cpu)); bool already_loaded = vmx->loaded_vmcs->cpu == cpu; - if (!vmm_exclusive) - kvm_cpu_vmxon(phys_addr); - else if (!already_loaded) - loaded_vmcs_clear(vmx->loaded_vmcs); - if (!already_loaded) { + loaded_vmcs_clear(vmx->loaded_vmcs); local_irq_disable(); crash_disable_local_vmclear(cpu); @@ -2321,11 +2311,6 @@ static void vmx_vcpu_put(struct kvm_vcpu *vcpu) vmx_vcpu_pi_put(vcpu); __vmx_load_host_state(to_vmx(vcpu)); - if (!vmm_exclusive) { - __loaded_vmcs_clear(to_vmx(vcpu)->loaded_vmcs); - vcpu->cpu = -1; - kvm_cpu_vmxoff(); - } } static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu); @@ -3416,6 +3401,7 @@ static __init int vmx_disabled_by_bios(void) static void kvm_cpu_vmxon(u64 addr) { + cr4_set_bits(X86_CR4_VMXE); intel_pt_handle_vmx(1); asm volatile (ASM_VMX_VMXON_RAX @@ -3458,12 +3444,8 @@ static int hardware_enable(void) /* enable and lock */ wrmsrl(MSR_IA32_FEATURE_CONTROL, old | test_bits); } - cr4_set_bits(X86_CR4_VMXE); - - if (vmm_exclusive) { - kvm_cpu_vmxon(phys_addr); - ept_sync_global(); - } + kvm_cpu_vmxon(phys_addr); + ept_sync_global(); native_store_gdt(this_cpu_ptr(&host_gdt)); @@ -3489,15 +3471,13 @@ static void kvm_cpu_vmxoff(void) asm volatile (__ex(ASM_VMX_VMXOFF) : : : "cc"); intel_pt_handle_vmx(0); + cr4_clear_bits(X86_CR4_VMXE); } static void hardware_disable(void) { - if (vmm_exclusive) { - vmclear_local_loaded_vmcss(); - kvm_cpu_vmxoff(); - } - cr4_clear_bits(X86_CR4_VMXE); + vmclear_local_loaded_vmcss(); + kvm_cpu_vmxoff(); } static __init int adjust_vmx_controls(u32 ctl_min, u32 ctl_opt, @@ -9228,11 +9208,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id) vmx->loaded_vmcs->shadow_vmcs = NULL; if (!vmx->loaded_vmcs->vmcs) goto free_msrs; - if (!vmm_exclusive) - kvm_cpu_vmxon(__pa(per_cpu(vmxarea, raw_smp_processor_id()))); loaded_vmcs_init(vmx->loaded_vmcs); - if (!vmm_exclusive) - kvm_cpu_vmxoff(); cpu = get_cpu(); vmx_vcpu_load(&vmx->vcpu, cpu); -- 2.9.3
