* [PATCH v2] KVM: VMX: drop I/O permission bitmaps
@ 2017-12-12 8:44 Quan Xu
2017-12-12 16:02 ` Paolo Bonzini
0 siblings, 1 reply; 3+ messages in thread
From: Quan Xu @ 2017-12-12 8:44 UTC (permalink / raw)
To: kvm; +Cc: linux-kernel, rkrcmar, jmattson, pbonzini, david, Quan Xu
From: Quan Xu <quan.xu0@gmail.com>
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 <jmattson@google.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Quan Xu <quan.xu0@gmail.com>
---
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);
--
1.7.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] KVM: VMX: drop I/O permission bitmaps
2017-12-12 8:44 [PATCH v2] KVM: VMX: drop I/O permission bitmaps Quan Xu
@ 2017-12-12 16:02 ` Paolo Bonzini
2017-12-12 16:10 ` David Hildenbrand
0 siblings, 1 reply; 3+ messages in thread
From: Paolo Bonzini @ 2017-12-12 16:02 UTC (permalink / raw)
To: Quan Xu, kvm; +Cc: linux-kernel, rkrcmar, jmattson, david
On 12/12/2017 09:44, Quan Xu wrote:
> From: Quan Xu <quan.xu0@gmail.com>
>
> 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 <jmattson@google.com>
> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
> Signed-off-by: Quan Xu <quan.xu0@gmail.com>
> ---
> 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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] KVM: VMX: drop I/O permission bitmaps
2017-12-12 16:02 ` Paolo Bonzini
@ 2017-12-12 16:10 ` David Hildenbrand
0 siblings, 0 replies; 3+ messages in thread
From: David Hildenbrand @ 2017-12-12 16:10 UTC (permalink / raw)
To: Paolo Bonzini, Quan Xu, kvm; +Cc: linux-kernel, rkrcmar, jmattson
> /*
> - * 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
>
Reviewed-by: David Hildenbrand <david@redhat.com>
--
Thanks,
David / dhildenb
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-12-12 16:02 ` Paolo Bonzini
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