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From: Paolo Bonzini <pbonzini@redhat.com>
To: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Jon Doron <arilou@gmail.com>,
	kvm@vger.kernel.org, linux-hyperv@vger.kernel.org
Subject: Re: [PATCH v11 4/7] x86/kvm/hyper-v: Add support for synthetic debugger capability
Date: Fri, 29 May 2020 14:17:55 +0200
Message-ID: <6102aaf8-0ee0-b6cd-dce3-bb91376a1b5e@redhat.com> (raw)
In-Reply-To: <87ftbjhrk0.fsf@vitty.brq.redhat.com>

On 29/05/20 14:08, Vitaly Kuznetsov wrote:
>> On 24/04/20 13:37, Jon Doron wrote:
>>> +static int syndbg_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host)
>>> +{
>>> +	struct kvm_hv_syndbg *syndbg = vcpu_to_hv_syndbg(vcpu);
>>> +
>>> +	if (!syndbg->active && !host)
>>> +		return 1;
>>> +
>> One small thing: is the ENABLE_CAP and active field needed?  Can you
>> just check if the guest has the syndbg CPUID bits set?
>>
> Yes, we can probably get away with a static capability (so userspace
> knows that the interface is supported and CPUID bit can be set) and
> check guest_cpuid_has() here but we don't have Hyper-V feature leaves
> exposed as X86_FEATURE_* (yet). It is probably possible to implement an
> interim solution by open coding the check with kvm_find_cpuid_entry() or
> something like that.

Yes, that would be fine if you just abstract it in its own function.

Paolo


  reply index

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-24 11:37 [PATCH v11 0/7] x86/kvm/hyper-v: add support for synthetic debugger Jon Doron
2020-04-24 11:37 ` [PATCH v11 1/7] x86/kvm/hyper-v: Explicitly align hcall param for kvm_hyperv_exit Jon Doron
2020-05-13  8:42   ` Roman Kagan
2020-04-24 11:37 ` [PATCH v11 2/7] x86/kvm/hyper-v: Simplify addition for custom cpuid leafs Jon Doron
2020-05-13  9:24   ` Roman Kagan
2020-05-13 12:49     ` Jon Doron
2020-05-29 11:13       ` Paolo Bonzini
2020-04-24 11:37 ` [PATCH v11 3/7] x86/hyper-v: Add synthetic debugger definitions Jon Doron
2020-04-24 11:37 ` [PATCH v11 4/7] x86/kvm/hyper-v: Add support for synthetic debugger capability Jon Doron
2020-05-29 10:46   ` Paolo Bonzini
2020-05-29 12:08     ` Vitaly Kuznetsov
2020-05-29 12:17       ` Paolo Bonzini [this message]
2020-04-24 11:37 ` [PATCH v11 5/7] x86/kvm/hyper-v: enable hypercalls without hypercall page with syndbg Jon Doron
2020-05-13  9:57   ` Roman Kagan
2020-05-13 12:37     ` Jon Doron
2020-05-29 10:48   ` Paolo Bonzini
2020-04-24 11:37 ` [PATCH v11 6/7] x86/kvm/hyper-v: Add support for synthetic debugger via hypercalls Jon Doron
2020-05-12 15:33   ` Roman Kagan
2020-05-13 12:39     ` Jon Doron
2020-04-24 11:37 ` [PATCH v11 7/7] KVM: selftests: update hyperv_cpuid with SynDBG tests Jon Doron
2020-05-07  3:01 ` [PATCH v11 0/7] x86/kvm/hyper-v: add support for synthetic debugger Jon Doron
2020-05-07  7:57   ` Paolo Bonzini

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