From: "Radim Krčmář" <rkrcmar@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, "Lan, Tianyu" <tianyu.lan@intel.com>,
Igor Mammedov <imammedo@redhat.com>,
Jan Kiszka <jan.kiszka@web.de>, Peter Xu <peterx@redhat.com>
Subject: Re: [PATCH 7/9] KVM: x86: use proper format of APIC ID register
Date: Wed, 25 May 2016 18:30:19 +0200 [thread overview]
Message-ID: <20160525163018.GG14795@potion> (raw)
In-Reply-To: <cead5a97-01c4-281b-db5b-bf844a3a95cb@redhat.com>
2016-05-17 17:34+0200, Paolo Bonzini:
> On 06/05/2016 22:54, Radim Krčmář wrote:
>> We currently always shift APIC ID as if APIC was in xAPIC mode.
>> x2APIC mode wants to use more bits and storing a hardware-compabible
>> value is the the sanest option. VMX can stop intercepting the APIC ID
>> register then.
>>
>> KVM API to set the lapic expects that bottom 8 bits of APIC ID are in
>> top 8 bits of APIC_ID register. Definite that x2APIC IDs are byte
>> swapped to keep compatibility without new toggles.
>
> That's a bit too clever... Can we make KVM_CAP_MSI_X2APIC an
> enable-able capability (and then better rename it KVM_CAP_X2APIC_ID),
> and then all ids become 32 bit? This fixes the APIC ID issue here, and
> avoids introducing a new routing type in patch 5.
>
> The cost is a little extra complexity in QEMU, but I think it's bearable.
Will do, thanks.
next prev parent reply other threads:[~2016-05-25 16:30 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-06 20:53 [RFC 0/9] KVM: x86: break the xAPIC barrier Radim Krčmář
2016-05-06 20:53 ` [PATCH 1/9] KVM: x86: add kvm_apic_map_get_dest_lapic Radim Krčmář
2016-05-19 6:36 ` Peter Xu
2016-05-25 16:02 ` Radim Krčmář
2016-05-26 11:58 ` Peter Xu
2016-05-06 20:53 ` [PATCH 2/9] KVM: x86: dynamic kvm_apic_map Radim Krčmář
2016-05-23 8:04 ` Peter Xu
2016-05-25 16:15 ` Radim Krčmář
2016-05-30 5:24 ` Peter Xu
2016-05-06 20:53 ` [PATCH 3/9] KVM: x86: use u16 for logical VCPU mask in lapic Radim Krčmář
2016-05-06 20:54 ` [PATCH 4/9] KVM: x86: use generic function for MSI parsing Radim Krčmář
2016-05-06 20:54 ` [PATCH 5/9] KVM: support x2APIC ID in userspace routes Radim Krčmář
2016-05-06 20:54 ` [PATCH 6/9] KVM: x86: directly call recalculate_apic_map on lapic restore Radim Krčmář
2016-05-23 8:30 ` Peter Xu
2016-05-06 20:54 ` [PATCH 7/9] KVM: x86: use proper format of APIC ID register Radim Krčmář
2016-05-17 15:34 ` Paolo Bonzini
2016-05-25 16:30 ` Radim Krčmář [this message]
2016-05-06 20:54 ` [PATCH 8/9] KVM: x86: reset lapic base in kvm_lapic_reset Radim Krčmář
2016-05-06 20:54 ` [PATCH 9/9] KVM: bump MAX_VCPUS Radim Krčmář
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