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Message-ID: <7ea9f2d8-6688-612c-21a8-f3f3517da122@redhat.com>
Date: Sun, 17 Jan 2021 19:20:29 +0100
From: Paolo Bonzini <pbonzini@...hat.com>
To: Wei Huang <whuang2@....com>, Wei Huang <wei.huang2@....com>,
kvm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, vkuznets@...hat.com,
seanjc@...gle.com, joro@...tes.org, bp@...en8.de,
tglx@...utronix.de, mingo@...hat.com, x86@...nel.org,
jmattson@...gle.com, wanpengli@...cent.com, bsd@...hat.com,
dgilbert@...hat.com, mlevitsk@...hat.com
Subject: Re: [PATCH 1/2] KVM: x86: Add emulation support for #GP triggered by
VM instructions
On 15/01/21 08:00, Wei Huang wrote:
> If the whole body inside if-statement is moved out, do you expect the
> interface of x86_emulate_decoded_instruction to be something like:
>
> int x86_emulate_decoded_instruction(struct kvm_vcpu *vcpu,
> gpa_t cr2_or_gpa,
> int emulation_type, void *insn,
> int insn_len,
> bool write_fault_to_spt)
An idea is to making the body of the new function just
init_emulate_ctxt(vcpu);
/*
* We will reenter on the same instruction since
* we do not set complete_userspace_io. This does not
* handle watchpoints yet, those would be handled in
* the emulate_ops.
*/
if (!(emulation_type & EMULTYPE_SKIP) &&
kvm_vcpu_check_breakpoint(vcpu, &r))
return r;
ctxt->interruptibility = 0;
ctxt->have_exception = false;
ctxt->exception.vector = -1;
ctxt->exception.error_code_valid = false;
ctxt->perm_ok = false;
ctxt->ud = emulation_type & EMULTYPE_TRAP_UD;
r = x86_decode_insn(ctxt, insn, insn_len);
trace_kvm_emulate_insn_start(vcpu);
++vcpu->stat.insn_emulation;
return r;
because for the new caller, on EMULATION_FAILED you can just re-enter
the guest.
> And if so, what is the emulation type to use when calling this function
> from svm.c? EMULTYPE_VMWARE_GP?
Just 0 I think.
Paolo
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