On 12/12/2017 09:44, Quan Xu wrote:
> From: Quan Xu
>
> Since KVM removes the only I/O port 0x80 bypass on Intel hosts,
> clear CPU_BASED_USE_IO_BITMAPS and set CPU_BASED_UNCOND_IO_EXITING
> bit. Then these I/O permission bitmaps are not used at all, so
> drop I/O permission bitmaps.
>
> Signed-off-by: Jim Mattson
> Signed-off-by: Radim Krčmář
> Signed-off-by: Quan Xu
> ---
> arch/x86/kvm/vmx.c | 15 +--
> 1 files changed, 1 insertions(+), 14 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 2fd9a8c..41aaf5e 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -943,8 +943,6 @@ 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 +956,6 @@ 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 +3628,7 @@ 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 |
> @@ -5445,10 +5441,6 @@ 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));
> @@ -6751,14 +6743,9 @@ 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);
>
>
Squashing this for documentation:
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 51967236486e..b016cf1b9f77 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10551,8 +10551,8 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct
vmcs12 *vmcs12,
}
/*
-* Merging of IO bitmap not currently supported.
-* Rather, exit every time.
+* A vmexit (to either L1 hypervisor or L0 userspace) is always needed
+* for I/O port accesses.
*/
exec_control &= ~CPU_BASED_USE_IO_BITMAPS;
exec_control |= CPU_BASED_UNCOND_IO_EXITING;
Thanks,
Paolo
