From 690908104e39d37947f89d76388c876ce4ec5fda Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 15 Apr 2019 15:16:17 +0200 Subject: [PATCH] KVM: nVMX: allow tests to use bad virtual-APIC page address As mentioned in the comment, there are some special cases where we can simply clear the TPR shadow bit from the CPU-based execution controls in the vmcs02. Handle them so that we can remove some XFAILs from vmx.flat. Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/nested.c | 25 ++++++++++++++++--------- arch/x86/kvm/vmx/vmx.c | 2 +- arch/x86/kvm/vmx/vmx.h | 2 ++ 3 files changed, 19 insertions(+), 10 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 7ec9bb1..a22af5a 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -2873,20 +2873,27 @@ static void nested_get_vmcs12_pages(struct kvm_vcpu *vcpu) /* * If translation failed, VM entry will fail because * prepare_vmcs02 set VIRTUAL_APIC_PAGE_ADDR to -1ull. - * Failing the vm entry is _not_ what the processor - * does but it's basically the only possibility we - * have. We could still enter the guest if CR8 load - * exits are enabled, CR8 store exits are enabled, and - * virtualize APIC access is disabled; in this case - * the processor would never use the TPR shadow and we - * could simply clear the bit from the execution - * control. But such a configuration is useless, so - * let's keep the code simple. */ if (!is_error_page(page)) { vmx->nested.virtual_apic_page = page; hpa = page_to_phys(vmx->nested.virtual_apic_page); vmcs_write64(VIRTUAL_APIC_PAGE_ADDR, hpa); + } else if (nested_cpu_has(vmcs12, CPU_BASED_CR8_LOAD_EXITING) && + nested_cpu_has(vmcs12, CPU_BASED_CR8_STORE_EXITING) && + !nested_cpu_has2(vmcs12, SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES)) { + /* + * The processor will never use the TPR shadow, simply + * clear the bit from the execution control. Such a + * configuration is useless, but it happens in tests. + * For any other configuration, failing the vm entry is + * _not_ what the processor does but it's basically the + * only possibility we have. + */ + vmcs_clear_bits(CPU_BASED_VM_EXEC_CONTROL, + CPU_BASED_TPR_SHADOW); + } else { + printk("bad virtual-APIC page address\n"); + dump_vmcs(); } } diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index ab432a9..7a8f75f 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -5603,7 +5603,7 @@ static void vmx_dump_dtsel(char *name, uint32_t limit) vmcs_readl(limit + GUEST_GDTR_BASE - GUEST_GDTR_LIMIT)); } -static void dump_vmcs(void) +void dump_vmcs(void) { u32 vmentry_ctl = vmcs_read32(VM_ENTRY_CONTROLS); u32 vmexit_ctl = vmcs_read32(VM_EXIT_CONTROLS); diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index a1e00d0..f879529 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -517,4 +517,6 @@ static inline void decache_tsc_multiplier(struct vcpu_vmx *vmx) vmcs_write64(TSC_MULTIPLIER, vmx->current_tsc_ratio); } +void dump_vmcs(void); + #endif /* __KVM_X86_VMX_H */ -- 2.7.4