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Commit 14168786 authored by Gleb Natapov's avatar Gleb Natapov Committed by Marcelo Tosatti
Browse files

KVM: VMX: set vmx->emulation_required only when needed. 



If emulate_invalid_guest_state=false vmx->emulation_required is never
actually used, but it ends up to be always set to true since
handle_invalid_guest_state(), the only place it is reset back to
false, is never called. This, besides been not very clean, makes vmexit
and vmentry path to check emulate_invalid_guest_state needlessly.

The patch fixes that by keeping emulation_required coherent with
emulate_invalid_guest_state setting.

Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent 378a8b09

arch/x86/kvm/vmx.c

+12 −7
Original line number Original line Diff line number Diff line
@@ -2759,6 +2759,11 @@ static __exit void hardware_unsetup(void) 
	free_kvm_area();

	free_kvm_area();

}

}





static bool emulation_required(struct kvm_vcpu *vcpu)

{

	return emulate_invalid_guest_state && !guest_state_valid(vcpu);

}



static void fix_pmode_seg(struct kvm_vcpu *vcpu, int seg,

static void fix_pmode_seg(struct kvm_vcpu *vcpu, int seg,

		struct kvm_segment *save)

		struct kvm_segment *save)

{

{
@@ -2794,7 +2799,6 @@ static void enter_pmode(struct kvm_vcpu *vcpu) 
	vmx_get_segment(vcpu, &vmx->rmode.segs[VCPU_SREG_SS], VCPU_SREG_SS);

	vmx_get_segment(vcpu, &vmx->rmode.segs[VCPU_SREG_SS], VCPU_SREG_SS);

	vmx_get_segment(vcpu, &vmx->rmode.segs[VCPU_SREG_CS], VCPU_SREG_CS);

	vmx_get_segment(vcpu, &vmx->rmode.segs[VCPU_SREG_CS], VCPU_SREG_CS);





	vmx->emulation_required = 1;

	vmx->rmode.vm86_active = 0;

	vmx->rmode.vm86_active = 0;





	vmx_segment_cache_clear(vmx);

	vmx_segment_cache_clear(vmx);
@@ -2885,7 +2889,6 @@ static void enter_rmode(struct kvm_vcpu *vcpu) 
	vmx_get_segment(vcpu, &vmx->rmode.segs[VCPU_SREG_SS], VCPU_SREG_SS);

	vmx_get_segment(vcpu, &vmx->rmode.segs[VCPU_SREG_SS], VCPU_SREG_SS);

	vmx_get_segment(vcpu, &vmx->rmode.segs[VCPU_SREG_CS], VCPU_SREG_CS);

	vmx_get_segment(vcpu, &vmx->rmode.segs[VCPU_SREG_CS], VCPU_SREG_CS);





	vmx->emulation_required = 1;

	vmx->rmode.vm86_active = 1;

	vmx->rmode.vm86_active = 1;





	/*

	/*
@@ -3111,6 +3114,9 @@ static void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0) 
	vmcs_writel(CR0_READ_SHADOW, cr0);

	vmcs_writel(CR0_READ_SHADOW, cr0);

	vmcs_writel(GUEST_CR0, hw_cr0);

	vmcs_writel(GUEST_CR0, hw_cr0);

	vcpu->arch.cr0 = cr0;

	vcpu->arch.cr0 = cr0;



	/* depends on vcpu->arch.cr0 to be set to a new value */

	vmx->emulation_required = emulation_required(vcpu);

}

}





static u64 construct_eptp(unsigned long root_hpa)

static u64 construct_eptp(unsigned long root_hpa)
@@ -3298,8 +3304,7 @@ static void vmx_set_segment(struct kvm_vcpu *vcpu, 
	vmcs_write32(sf->ar_bytes, vmx_segment_access_rights(var));

	vmcs_write32(sf->ar_bytes, vmx_segment_access_rights(var));





out:

out:

	if (!vmx->emulation_required)

	vmx->emulation_required |= emulation_required(vcpu);

		vmx->emulation_required = !guest_state_valid(vcpu);

}

}





static void vmx_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l)

static void vmx_get_cs_db_l_bits(struct kvm_vcpu *vcpu, int *db, int *l)
@@ -5027,7 +5032,7 @@ static int handle_invalid_guest_state(struct kvm_vcpu *vcpu) 
			schedule();

			schedule();

	}

	}





	vmx->emulation_required = !guest_state_valid(vcpu);

	vmx->emulation_required = emulation_required(vcpu);

out:

out:

	return ret;

	return ret;

}

}
@@ -5970,7 +5975,7 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu) 
	u32 vectoring_info = vmx->idt_vectoring_info;

	u32 vectoring_info = vmx->idt_vectoring_info;





	/* If guest state is invalid, start emulating */

	/* If guest state is invalid, start emulating */

	if (vmx->emulation_required && emulate_invalid_guest_state)

	if (vmx->emulation_required)

		return handle_invalid_guest_state(vcpu);

		return handle_invalid_guest_state(vcpu);





	/*

	/*
@@ -6253,7 +6258,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) 




	/* Don't enter VMX if guest state is invalid, let the exit handler

	/* Don't enter VMX if guest state is invalid, let the exit handler

	   start emulation until we arrive back to a valid state */

	   start emulation until we arrive back to a valid state */

	if (vmx->emulation_required && emulate_invalid_guest_state)

	if (vmx->emulation_required)

		return;

		return;





	if (test_bit(VCPU_REGS_RSP, (unsigned long *)&vcpu->arch.regs_dirty))

	if (test_bit(VCPU_REGS_RSP, (unsigned long *)&vcpu->arch.regs_dirty))