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Message-ID: <5085857e16cdb133803ee3edf3b1e8b776b2a7b1.camel@intel.com>
Subject: Re: [PATCH v7 050/102] KVM: VMX: Split out guts of EPT violation to
 common/exposed function
From:   Kai Huang <kai.huang@intel.com>
To:     isaku.yamahata@intel.com, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     isaku.yamahata@gmail.com, Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>
Date:   Fri, 08 Jul 2022 22:25:05 +1200
In-Reply-To: <5202bef37eb1d9683891f29ccba182bbdceafca4.1656366338.git.isaku.yamahata@intel.com>
References: <cover.1656366337.git.isaku.yamahata@intel.com>
         <5202bef37eb1d9683891f29ccba182bbdceafca4.1656366338.git.isaku.yamahata@intel.com>
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On Mon, 2022-06-27 at 14:53 -0700, isaku.yamahata@intel.com wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
>=20
> The difference of TDX EPT violation is how to retrieve information, GPA,
> and exit qualification.  To share the code to handle EPT violation, split
> out the guts of EPT violation handler so that VMX/TDX exit handler can ca=
ll
> it after retrieving GPA and exit qualification.
>=20
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  arch/x86/kvm/vmx/common.h | 33 +++++++++++++++++++++++++++++++++
>  arch/x86/kvm/vmx/vmx.c    | 32 ++++++--------------------------
>  2 files changed, 39 insertions(+), 26 deletions(-)
>  create mode 100644 arch/x86/kvm/vmx/common.h
>=20
> diff --git a/arch/x86/kvm/vmx/common.h b/arch/x86/kvm/vmx/common.h
> new file mode 100644
> index 000000000000..235908f3e044
> --- /dev/null
> +++ b/arch/x86/kvm/vmx/common.h
> @@ -0,0 +1,33 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +#ifndef __KVM_X86_VMX_COMMON_H
> +#define __KVM_X86_VMX_COMMON_H
> +
> +#include <linux/kvm_host.h>
> +
> +#include "mmu.h"
> +
> +static inline int __vmx_handle_ept_violation(struct kvm_vcpu *vcpu, gpa_=
t gpa,
> +					     unsigned long exit_qualification)
> +{
> +	u64 error_code;
> +
> +	/* Is it a read fault? */
> +	error_code =3D (exit_qualification & EPT_VIOLATION_ACC_READ)
> +		     ? PFERR_USER_MASK : 0;
> +	/* Is it a write fault? */
> +	error_code |=3D (exit_qualification & EPT_VIOLATION_ACC_WRITE)
> +		      ? PFERR_WRITE_MASK : 0;
> +	/* Is it a fetch fault? */
> +	error_code |=3D (exit_qualification & EPT_VIOLATION_ACC_INSTR)
> +		      ? PFERR_FETCH_MASK : 0;
> +	/* ept page table entry is present? */
> +	error_code |=3D (exit_qualification & EPT_VIOLATION_RWX_MASK)
> +		      ? PFERR_PRESENT_MASK : 0;
> +
> +	error_code |=3D (exit_qualification & EPT_VIOLATION_GVA_TRANSLATED) !=
=3D 0 ?
> +	       PFERR_GUEST_FINAL_MASK : PFERR_GUEST_PAGE_MASK;
> +
> +	return kvm_mmu_page_fault(vcpu, gpa, error_code, NULL, 0);
> +}
> +
> +#endif /* __KVM_X86_VMX_COMMON_H */
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index e3d304b14df0..2f1dc06aec3c 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -50,6 +50,7 @@
>  #include <asm/vmx.h>
> =20
>  #include "capabilities.h"
> +#include "common.h"
>  #include "cpuid.h"
>  #include "evmcs.h"
>  #include "hyperv.h"
> @@ -5578,11 +5579,10 @@ static int handle_task_switch(struct kvm_vcpu *vc=
pu)
> =20
>  static int handle_ept_violation(struct kvm_vcpu *vcpu)
>  {
> -	unsigned long exit_qualification;
> -	gpa_t gpa;
> -	u64 error_code;
> +	unsigned long exit_qualification =3D vmx_get_exit_qual(vcpu);
> +	gpa_t gpa =3D vmcs_read64(GUEST_PHYSICAL_ADDRESS);
> =20
> -	exit_qualification =3D vmx_get_exit_qual(vcpu);
> +	trace_kvm_page_fault(gpa, exit_qualification);
> =20
>  	/*
>  	 * EPT violation happened while executing iret from NMI,
> @@ -5591,29 +5591,9 @@ static int handle_ept_violation(struct kvm_vcpu *v=
cpu)
>  	 * AAK134, BY25.
>  	 */
>  	if (!(to_vmx(vcpu)->idt_vectoring_info & VECTORING_INFO_VALID_MASK) &&
> -			enable_vnmi &&
> -			(exit_qualification & INTR_INFO_UNBLOCK_NMI))
> +	    enable_vnmi && (exit_qualification & INTR_INFO_UNBLOCK_NMI))

Why this code change?

With this removed:

Reviewed-by: Kai Huang <kai.huang@intel.com>

>  		vmcs_set_bits(GUEST_INTERRUPTIBILITY_INFO, GUEST_INTR_STATE_NMI);
> =20
> -	gpa =3D vmcs_read64(GUEST_PHYSICAL_ADDRESS);
> -	trace_kvm_page_fault(gpa, exit_qualification);
> -
> -	/* Is it a read fault? */
> -	error_code =3D (exit_qualification & EPT_VIOLATION_ACC_READ)
> -		     ? PFERR_USER_MASK : 0;
> -	/* Is it a write fault? */
> -	error_code |=3D (exit_qualification & EPT_VIOLATION_ACC_WRITE)
> -		      ? PFERR_WRITE_MASK : 0;
> -	/* Is it a fetch fault? */
> -	error_code |=3D (exit_qualification & EPT_VIOLATION_ACC_INSTR)
> -		      ? PFERR_FETCH_MASK : 0;
> -	/* ept page table entry is present? */
> -	error_code |=3D (exit_qualification & EPT_VIOLATION_RWX_MASK)
> -		      ? PFERR_PRESENT_MASK : 0;
> -
> -	error_code |=3D (exit_qualification & EPT_VIOLATION_GVA_TRANSLATED) !=
=3D 0 ?
> -	       PFERR_GUEST_FINAL_MASK : PFERR_GUEST_PAGE_MASK;
> -
>  	vcpu->arch.exit_qualification =3D exit_qualification;
> =20
>  	/*
> @@ -5627,7 +5607,7 @@ static int handle_ept_violation(struct kvm_vcpu *vc=
pu)
>  	if (unlikely(allow_smaller_maxphyaddr && kvm_vcpu_is_illegal_gpa(vcpu, =
gpa)))
>  		return kvm_emulate_instruction(vcpu, 0);
> =20
> -	return kvm_mmu_page_fault(vcpu, gpa, error_code, NULL, 0);
> +	return __vmx_handle_ept_violation(vcpu, gpa, exit_qualification);
>  }
> =20
>  static int handle_ept_misconfig(struct kvm_vcpu *vcpu)