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Date: Wed, 28 Jan 2015 23:52:25 +0800
From: Wincy Van <fanwenyi0529@...il.com>
To: Paolo Bonzini <pbonzini@...hat.com>,
"gleb@...nel.org" <gleb@...nel.org>,
"Zhang, Yang Z" <yang.z.zhang@...el.com>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"kvm@...r.kernel.org" <kvm@...r.kernel.org>,
Wanpeng Li <wanpeng.li@...ux.intel.com>,
Jan Kiszka <jan.kiszka@....de>,
θζδΈ <fanwenyi0529@...il.com>
Subject: Re: [PATCH v4 1/6] KVM: nVMX: Use hardware MSR bitmap
Sorry, please ignore this mail, the subject is wrong : (
On Wed, Jan 28, 2015 at 11:50 PM, Wincy Van <fanwenyi0529@...il.com> wrote:
> Currently, if L1 enables MSR_BITMAP, we will emulate this feature,
> all of L2's msr access is intercepted by L0. Since many features
> like virtualize x2apic mode has a complicated logic and it is
> difficult for us to emulate, we should use hardware and merge
> the bitmap.
>
> This patch introduces nested_vmx_merge_msr_bitmap for future use.
>
> Signed-off-by: Wincy Van <fanwenyi0529@...il.com>
> ---
> arch/x86/kvm/vmx.c | 77 ++++++++++++++++++++++++++++++++++++++++++++-------
> 1 files changed, 66 insertions(+), 11 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index c987374..787f886 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -798,6 +798,7 @@ static unsigned long *vmx_msr_bitmap_legacy;
> static unsigned long *vmx_msr_bitmap_longmode;
> static unsigned long *vmx_msr_bitmap_legacy_x2apic;
> static unsigned long *vmx_msr_bitmap_longmode_x2apic;
> +static unsigned long *vmx_msr_bitmap_nested;
> static unsigned long *vmx_vmread_bitmap;
> static unsigned long *vmx_vmwrite_bitmap;
>
> @@ -5812,13 +5813,21 @@ static __init int hardware_setup(void)
> (unsigned long *)__get_free_page(GFP_KERNEL);
> if (!vmx_msr_bitmap_longmode_x2apic)
> goto out4;
> +
> + if (nested) {
> + vmx_msr_bitmap_nested =
> + (unsigned long *)__get_free_page(GFP_KERNEL);
> + if (!vmx_msr_bitmap_nested)
> + goto out5;
> + }
> +
> vmx_vmread_bitmap = (unsigned long *)__get_free_page(GFP_KERNEL);
> if (!vmx_vmread_bitmap)
> - goto out5;
> + goto out6;
>
> vmx_vmwrite_bitmap = (unsigned long *)__get_free_page(GFP_KERNEL);
> if (!vmx_vmwrite_bitmap)
> - goto out6;
> + goto out7;
>
> memset(vmx_vmread_bitmap, 0xff, PAGE_SIZE);
> memset(vmx_vmwrite_bitmap, 0xff, PAGE_SIZE);
> @@ -5834,10 +5843,12 @@ static __init int hardware_setup(void)
>
> memset(vmx_msr_bitmap_legacy, 0xff, PAGE_SIZE);
> memset(vmx_msr_bitmap_longmode, 0xff, PAGE_SIZE);
> + if (nested)
> + memset(vmx_msr_bitmap_nested, 0xff, PAGE_SIZE);
>
> if (setup_vmcs_config(&vmcs_config) < 0) {
> r = -EIO;
> - goto out7;
> + goto out8;
> }
>
> if (boot_cpu_has(X86_FEATURE_NX))
> @@ -5944,10 +5955,13 @@ static __init int hardware_setup(void)
>
> return alloc_kvm_area();
>
> -out7:
> +out8:
> free_page((unsigned long)vmx_vmwrite_bitmap);
> -out6:
> +out7:
> free_page((unsigned long)vmx_vmread_bitmap);
> +out6:
> + if (nested)
> + free_page((unsigned long)vmx_msr_bitmap_nested);
> out5:
> free_page((unsigned long)vmx_msr_bitmap_longmode_x2apic);
> out4:
> @@ -5974,6 +5988,8 @@ static __exit void hardware_unsetup(void)
> free_page((unsigned long)vmx_io_bitmap_a);
> free_page((unsigned long)vmx_vmwrite_bitmap);
> free_page((unsigned long)vmx_vmread_bitmap);
> + if (nested)
> + free_page((unsigned long)vmx_msr_bitmap_nested);
>
> free_kvm_area();
> }
> @@ -8305,6 +8321,38 @@ static void vmx_start_preemption_timer(struct
> kvm_vcpu *vcpu)
> ns_to_ktime(preemption_timeout), HRTIMER_MODE_REL);
> }
>
> +static int nested_vmx_check_msr_bitmap_controls(struct kvm_vcpu *vcpu,
> + struct vmcs12 *vmcs12)
> +{
> + int maxphyaddr;
> + u64 addr;
> +
> + if (!nested_cpu_has(vmcs12, CPU_BASED_USE_MSR_BITMAPS))
> + return 0;
> +
> + if (vmcs12_read_any(vcpu, MSR_BITMAP, &addr)) {
> + WARN_ON(1);
> + return -EINVAL;
> + }
> + maxphyaddr = cpuid_maxphyaddr(vcpu);
> +
> + if (!PAGE_ALIGNED(vmcs12->msr_bitmap) ||
> + ((addr + PAGE_SIZE) >> maxphyaddr))
> + return -EINVAL;
> +
> + return 0;
> +}
> +
> +/*
> + * Merge L0's and L1's MSR bitmap, return false to indicate that
> + * we do not use the hardware.
> + */
> +static inline bool nested_vmx_merge_msr_bitmap(struct kvm_vcpu *vcpu,
> + struct vmcs12 *vmcs12)
> +{
> + return false;
> +}
> +
> static int nested_vmx_check_msr_switch(struct kvm_vcpu *vcpu,
> unsigned long count_field,
> unsigned long addr_field,
> @@ -8637,11 +8685,17 @@ static void prepare_vmcs02(struct kvm_vcpu
> *vcpu, struct vmcs12 *vmcs12)
> vmcs_write32(TPR_THRESHOLD, vmcs12->tpr_threshold);
> }
>
> + if (cpu_has_vmx_msr_bitmap() &&
> + exec_control & CPU_BASED_USE_MSR_BITMAPS &&
> + nested_vmx_merge_msr_bitmap(vcpu, vmcs12)) {
> + vmcs_write64(MSR_BITMAP, __pa(vmx_msr_bitmap_nested));
> + } else
> + exec_control &= ~CPU_BASED_USE_MSR_BITMAPS;
> +
> /*
> - * Merging of IO and MSR bitmaps not currently supported.
> + * Merging of IO bitmap not currently supported.
> * Rather, exit every time.
> */
> - exec_control &= ~CPU_BASED_USE_MSR_BITMAPS;
> exec_control &= ~CPU_BASED_USE_IO_BITMAPS;
> exec_control |= CPU_BASED_UNCOND_IO_EXITING;
>
> @@ -8792,15 +8846,13 @@ static int nested_vmx_run(struct kvm_vcpu
> *vcpu, bool launch)
> return 1;
> }
>
> - if ((vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_MSR_BITMAPS) &&
> - !PAGE_ALIGNED(vmcs12->msr_bitmap)) {
> + if (!nested_get_vmcs12_pages(vcpu, vmcs12)) {
> /*TODO: Also verify bits beyond physical address width are 0*/
> nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
> return 1;
> }
>
> - if (!nested_get_vmcs12_pages(vcpu, vmcs12)) {
> - /*TODO: Also verify bits beyond physical address width are 0*/
> + if (nested_vmx_check_msr_bitmap_controls(vcpu, vmcs12)) {
> nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD);
> return 1;
> }
> @@ -9356,6 +9408,9 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu,
> kvm_set_dr(vcpu, 7, 0x400);
> vmcs_write64(GUEST_IA32_DEBUGCTL, 0);
>
> + if (cpu_has_vmx_msr_bitmap())
> + vmx_set_msr_bitmap(vcpu);
> +
> if (nested_vmx_load_msr(vcpu, vmcs12->vm_exit_msr_load_addr,
> vmcs12->vm_exit_msr_load_count))
> nested_vmx_abort(vcpu, VMX_ABORT_LOAD_HOST_MSR_FAIL);
> --
> 1.7.1
--
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