On Wed, Dec 6, 2017 at 3:17 AM, Quan Xu <quan.xu0@xxxxxxxxx> wrote:
>
>
> On 2017/12/06 05:26, Radim Krčmář wrote:
>>
>> 2017-12-01 10:21-0800, Jim Mattson:
>>>
>>> Since we no longer allow any I/O ports to be passed through to the guest,
>>> we can use the same page for I/O bitmap A and I/O bitmap B.
>>
>> I think we can disable the feature and save the second page as well:
>>
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index e25c55ea2eb7..80859a7cdf6d 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -3624,7 +3624,7 @@ static __init int setup_vmcs_config(struct
>> vmcs_config *vmcs_conf)
>> #endif
>> CPU_BASED_CR3_LOAD_EXITING |
>> CPU_BASED_CR3_STORE_EXITING |
>> - CPU_BASED_USE_IO_BITMAPS |
>> + CPU_BASED_UNCOND_IO_EXITING |
>> CPU_BASED_MOV_DR_EXITING |
>> CPU_BASED_USE_TSC_OFFSETING |
>> CPU_BASED_INVLPG_EXITING |
>>
>
> Jim / Radim,
>
>
> As a logical processor uses these bitmaps if and only if the “use I/O
> bitmaps” control is 1.
>
> Since we drop 'CPU_BASED_USE_IOBITMAPS' in vmcs configuration.. We could
> also drop
> 'IO_BITMAP_A'/'IO_BITMAP_B'/'vmx_io_bitmap_a'/'vmx_io_bitmap_b' for a
> furthermore
> cleanup as below:
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 04b4dbc..3e4f760 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -771,8 +771,6 @@ static struct pi_desc *vcpu_to_pi_desc(struct kvm_vcpu
> *vcpu)
> FIELD(HOST_FS_SELECTOR, host_fs_selector),
> FIELD(HOST_GS_SELECTOR, host_gs_selector),
> FIELD(HOST_TR_SELECTOR, host_tr_selector),
> - FIELD64(IO_BITMAP_A, io_bitmap_a),
> - FIELD64(IO_BITMAP_B, io_bitmap_b),
Stet.
> FIELD64(MSR_BITMAP, msr_bitmap),
> FIELD64(VM_EXIT_MSR_STORE_ADDR, vm_exit_msr_store_addr),
> FIELD64(VM_EXIT_MSR_LOAD_ADDR, vm_exit_msr_load_addr),
> @@ -943,8 +941,6 @@ static bool nested_vmx_is_page_fault_vmexit(struct
> vmcs12 *vmcs12,
> static DEFINE_PER_CPU(spinlock_t, blocked_vcpu_on_cpu_lock);
>
> enum {
> - VMX_IO_BITMAP_A,
> - VMX_IO_BITMAP_B,
> VMX_MSR_BITMAP_LEGACY,
> VMX_MSR_BITMAP_LONGMODE,
> VMX_MSR_BITMAP_LEGACY_X2APIC_APICV,
> @@ -958,8 +954,6 @@ enum {
>
> static unsigned long *vmx_bitmap[VMX_BITMAP_NR];
>
> -#define vmx_io_bitmap_a (vmx_bitmap[VMX_IO_BITMAP_A])
> -#define vmx_io_bitmap_b (vmx_bitmap[VMX_IO_BITMAP_B])
> #define vmx_msr_bitmap_legacy (vmx_bitmap[VMX_MSR_BITMAP_LEGACY])
> #define vmx_msr_bitmap_longmode (vmx_bitmap[VMX_MSR_BITMAP_LONGMODE])
> #define vmx_msr_bitmap_legacy_x2apic_apicv
> (vmx_bitmap[VMX_MSR_BITMAP_LEGACY_X2APIC_APICV])
> @@ -3632,7 +3626,7 @@ static __init int setup_vmcs_config(struct vmcs_config
> *vmcs_conf)
> #endif
> CPU_BASED_CR3_LOAD_EXITING |
> CPU_BASED_CR3_STORE_EXITING |
> - CPU_BASED_USE_IO_BITMAPS |
> + CPU_BASED_UNCOND_IO_EXITING |
Is it safe to assume that all CPUs (both physical and virtual)
currently running kvm will support this control bit?
> CPU_BASED_MOV_DR_EXITING |
> CPU_BASED_USE_TSC_OFFSETING |
> CPU_BASED_INVLPG_EXITING |
> @@ -5445,10 +5439,6 @@ static void vmx_vcpu_setup(struct vcpu_vmx *vmx)
> #endif
> int i;
>
> - /* I/O */
> - vmcs_write64(IO_BITMAP_A, __pa(vmx_io_bitmap_a));
> - vmcs_write64(IO_BITMAP_B, __pa(vmx_io_bitmap_b));
> -
> if (enable_shadow_vmcs) {
> vmcs_write64(VMREAD_BITMAP, __pa(vmx_vmread_bitmap));
> vmcs_write64(VMWRITE_BITMAP, __pa(vmx_vmwrite_bitmap));
> @@ -6751,13 +6741,9 @@ static __init int hardware_setup(void)
> goto out;
> }
>
> - vmx_io_bitmap_b = (unsigned long *)__get_free_page(GFP_KERNEL);
> memset(vmx_vmread_bitmap, 0xff, PAGE_SIZE);
> memset(vmx_vmwrite_bitmap, 0xff, PAGE_SIZE);
>
> - memset(vmx_io_bitmap_a, 0xff, PAGE_SIZE);
> - memset(vmx_io_bitmap_b, 0xff, PAGE_SIZE);
> -
> memset(vmx_msr_bitmap_legacy, 0xff, PAGE_SIZE);
> memset(vmx_msr_bitmap_longmode, 0xff, PAGE_SIZE);
>
>
>
>
>
> Quan
> Alibaba Cloud
