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SubjectRe: [PATCH v3 2/4] KVM/X86: Intel MPX vmx and msr handle
Il 21/01/2014 20:01, Liu, Jinsong ha scritto:
> From 31e68d752ac395dc6b65e6adf45be5324e92cdc8 Mon Sep 17 00:00:00 2001
> From: Liu Jinsong <jinsong.liu@intel.com>
> Date: Fri, 13 Dec 2013 02:32:43 +0800
> Subject: [PATCH v3 2/4] KVM/X86: Intel MPX vmx and msr handle
>
> This patch handle vmx and msr of Intel MPX feature.
>
> Signed-off-by: Xudong Hao <xudong.hao@intel.com>
> Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
> ---
> arch/x86/include/asm/vmx.h | 2 ++
> arch/x86/include/uapi/asm/msr-index.h | 1 +
> arch/x86/kvm/vmx.c | 12 ++++++++++--
> 3 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
> index 966502d..1bf4681 100644
> --- a/arch/x86/include/asm/vmx.h
> +++ b/arch/x86/include/asm/vmx.h
> @@ -85,6 +85,7 @@
> #define VM_EXIT_SAVE_IA32_EFER 0x00100000
> #define VM_EXIT_LOAD_IA32_EFER 0x00200000
> #define VM_EXIT_SAVE_VMX_PREEMPTION_TIMER 0x00400000
> +#define VM_EXIT_CLEAR_BNDCFGS 0x00800000
>
> #define VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR 0x00036dff
>
> @@ -95,6 +96,7 @@
> #define VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL 0x00002000
> #define VM_ENTRY_LOAD_IA32_PAT 0x00004000
> #define VM_ENTRY_LOAD_IA32_EFER 0x00008000
> +#define VM_ENTRY_LOAD_BNDCFGS 0x00010000
>
> #define VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR 0x000011ff
>
> diff --git a/arch/x86/include/uapi/asm/msr-index.h b/arch/x86/include/uapi/asm/msr-index.h
> index 37813b5..2a418c4 100644
> --- a/arch/x86/include/uapi/asm/msr-index.h
> +++ b/arch/x86/include/uapi/asm/msr-index.h
> @@ -294,6 +294,7 @@
> #define MSR_SMI_COUNT 0x00000034
> #define MSR_IA32_FEATURE_CONTROL 0x0000003a
> #define MSR_IA32_TSC_ADJUST 0x0000003b
> +#define MSR_IA32_BNDCFGS 0x00000d90
>
> #define FEATURE_CONTROL_LOCKED (1<<0)
> #define FEATURE_CONTROL_VMXON_ENABLED_INSIDE_SMX (1<<1)
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index b2fe1c2..6d7d9ad 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -439,6 +439,7 @@ struct vcpu_vmx {
> #endif
> int gs_ldt_reload_needed;
> int fs_reload_needed;
> + u64 msr_host_bndcfgs;
> } host_state;
> struct {
> int vm86_active;
> @@ -1647,6 +1648,8 @@ static void vmx_save_host_state(struct kvm_vcpu *vcpu)
> if (is_long_mode(&vmx->vcpu))
> wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);
> #endif
> + if (boot_cpu_has(X86_FEATURE_MPX))
> + rdmsrl(MSR_IA32_BNDCFGS, vmx->host_state.msr_host_bndcfgs);
> for (i = 0; i < vmx->save_nmsrs; ++i)
> kvm_set_shared_msr(vmx->guest_msrs[i].index,
> vmx->guest_msrs[i].data,
> @@ -1684,6 +1687,8 @@ static void __vmx_load_host_state(struct vcpu_vmx *vmx)
> #ifdef CONFIG_X86_64
> wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base);
> #endif
> + if (vmx->host_state.msr_host_bndcfgs)
> + wrmsrl(MSR_IA32_BNDCFGS, vmx->host_state.msr_host_bndcfgs);
> /*
> * If the FPU is not active (through the host task or
> * the guest vcpu), then restore the cr0.TS bit.
> @@ -2800,7 +2805,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
> min |= VM_EXIT_HOST_ADDR_SPACE_SIZE;
> #endif
> opt = VM_EXIT_SAVE_IA32_PAT | VM_EXIT_LOAD_IA32_PAT |
> - VM_EXIT_ACK_INTR_ON_EXIT;
> + VM_EXIT_ACK_INTR_ON_EXIT | VM_EXIT_CLEAR_BNDCFGS;
> if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_EXIT_CTLS,
> &_vmexit_control) < 0)
> return -EIO;
> @@ -2817,7 +2822,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
> _pin_based_exec_control &= ~PIN_BASED_POSTED_INTR;
>
> min = 0;
> - opt = VM_ENTRY_LOAD_IA32_PAT;
> + opt = VM_ENTRY_LOAD_IA32_PAT | VM_ENTRY_LOAD_BNDCFGS;
> if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_ENTRY_CTLS,
> &_vmentry_control) < 0)
> return -EIO;

You need to disable MPX in the guest if the two controls are not
available. You can do this, for example, in vmx_cpuid_update.
Otherwise, nested VMX is broken.

> @@ -8636,6 +8641,9 @@ static int __init vmx_init(void)
> vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_CS, false);
> vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_ESP, false);
> vmx_disable_intercept_for_msr(MSR_IA32_SYSENTER_EIP, false);
> + if (boot_cpu_has(X86_FEATURE_MPX))
> + vmx_disable_intercept_for_msr(MSR_IA32_BNDCFGS, true);

This needs to be done unconditionally. Otherwise, reading/writing
BNDCFGS will access a nonexistent VMCS field.

Paolo

> memcpy(vmx_msr_bitmap_legacy_x2apic,
> vmx_msr_bitmap_legacy, PAGE_SIZE);
> memcpy(vmx_msr_bitmap_longmode_x2apic,
>



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