From: Xiaoyao Li <xiaoyao.li@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Chenyi Qiang <chenyi.qiang@intel.com>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RESEND PATCH 1/2] KVM: X86: Add support for the emulation of DR6_BUS_LOCK bit
Date: Wed, 27 Jan 2021 11:41:21 +0800 [thread overview]
Message-ID: <5f3089a2-5a5c-a839-9ed9-471c404738a3@intel.com> (raw)
In-Reply-To: <fc29c63f-7820-078a-7d92-4a7adf828067@redhat.com>
On 1/27/2021 12:31 AM, Paolo Bonzini wrote:
> On 08/01/21 07:49, Chenyi Qiang wrote:
>> To avoid breaking the CPUs without bus lock detection, activate the
>> DR6_BUS_LOCK bit (bit 11) conditionally in DR6_FIXED_1 bits.
>>
>> The set/clear of DR6_BUS_LOCK is similar to the DR6_RTM in DR6
>> register. The processor clears DR6_BUS_LOCK when bus lock debug
>> exception is generated. (For all other #DB the processor sets this bit
>> to 1.) Software #DB handler should set this bit before returning to the
>> interrupted task.
>>
>> For VM exit caused by debug exception, bit 11 of the exit qualification
>> is set to indicate that a bus lock debug exception condition was
>> detected. The VMM should emulate the exception by clearing bit 11 of the
>> guest DR6.
>
> Please rename DR6_INIT to DR6_ACTIVE_LOW, and then a lot of changes
> become simpler:
Paolo,
What do you want to convey with the new name DR6_ACTIVE_LOW? To be
honest, the new name is confusing to me.
>> - dr6 |= DR6_BD | DR6_RTM;
>> + dr6 |= DR6_BD | DR6_RTM | DR6_BUS_LOCK;
>
> dr6 |= DR6_BD | DR6_ACTIVE_LOW;
>
next prev parent reply other threads:[~2021-01-27 6:13 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-08 6:49 [RESEND PATCH 0/2] Add KVM support for bus lock debug exception Chenyi Qiang
2021-01-08 6:49 ` [RESEND PATCH 1/2] KVM: X86: Add support for the emulation of DR6_BUS_LOCK bit Chenyi Qiang
2021-01-08 16:38 ` kernel test robot
2021-01-26 16:31 ` Paolo Bonzini
2021-01-27 1:48 ` Chenyi Qiang
2021-01-27 3:41 ` Xiaoyao Li [this message]
2021-01-27 10:04 ` Paolo Bonzini
2021-01-28 7:17 ` Xiaoyao Li
2021-01-28 7:25 ` Paolo Bonzini
2021-01-28 7:41 ` Xiaoyao Li
2021-01-08 6:49 ` [RESEND PATCH 2/2] KVM: X86: Expose bus lock debug exception to guest Chenyi Qiang
2021-01-08 18:16 ` kernel test robot
2021-01-26 16:33 ` Paolo Bonzini
2021-01-27 0:57 ` Chenyi Qiang
2021-01-27 12:31 ` Paolo Bonzini
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