From: Emanuele Giuseppe Esposito <eesposit@redhat.com>
To: Jim Mattson <jmattson@google.com>
Cc: kvm@vger.kernel.org, Ben Serebrin <serebrin@google.com>,
Peter Shier <pshier@google.com>,
Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Maxim Levitsky <mlevitsk@redhat.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/3] KVM: support the cpu feature FLUSH_L1D
Date: Tue, 21 Mar 2023 09:40:59 +0100 [thread overview]
Message-ID: <03df0429-9fb2-5326-9bf8-47367818fd49@redhat.com> (raw)
In-Reply-To: <CALMp9eTt3xzAEoQ038bJQ9LN0ZOXrSWsN7xnNUD+0SS=WwF7Pg@mail.gmail.com>
Am 20/03/2023 um 17:52 schrieb Jim Mattson:
> On Wed, Feb 1, 2023 at 5:29 AM Emanuele Giuseppe Esposito
> <eesposit@redhat.com> wrote:
>>
>> As the title suggest, if the host cpu supports flush_l1d flag and
>> QEMU/userspace wants to boot a VM with the same flag (or emulate same
>> host features), KVM should be able to do so.
>>
>> Patch 3 is the main fix, because if flush_l1d is not advertised by
>> KVM, a linux VM will erroneously mark
>> /sys/devices/system/cpu/vulnerabilities/mmio_stale_data
>> as vulnerable, even though it isn't since the host has the feature
>> and takes care of this. Not sure what would happen in the nested case though.
>>
>> Patch 1 and 2 are just taken and refactored from Jim Mattison's serie that it
>> seems was lost a while ago:
>> https://patchwork.kernel.org/project/kvm/patch/20180814173049.21756-1-jmattson@google.com/
>>
>> I thought it was worth re-posting them.
>
> What has changed since the patches were originally posted, and Konrad
> dissed them?
>
From the upstream conversation, I honestly didn't really catch that
Konrad dissed them. Or at least, I didn't read a valid reason for doing
so, contrary to what Sean instead provided. I thought it was just forgotten.
My bad, next time I will be more careful when trying to resume old
patches :)
Thank you,
Emanuele
next prev parent reply other threads:[~2023-03-21 8:42 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-01 13:29 Emanuele Giuseppe Esposito
2023-02-01 13:29 ` [PATCH 1/3] kvm: vmx: Add IA32_FLUSH_CMD guest support Emanuele Giuseppe Esposito
2023-03-17 19:04 ` Nathan Chancellor
2023-03-17 22:53 ` Pawan Gupta
2023-03-17 23:14 ` Nathan Chancellor
2023-03-17 23:59 ` Pawan Gupta
2023-03-20 14:53 ` Sean Christopherson
2023-03-20 15:40 ` Emanuele Giuseppe Esposito
2023-03-20 16:24 ` Sean Christopherson
2023-03-20 16:48 ` Emanuele Giuseppe Esposito
2023-03-21 23:59 ` Sean Christopherson
2023-02-01 13:29 ` [PATCH 2/3] kvm: svm: " Emanuele Giuseppe Esposito
2023-02-01 13:29 ` [PATCH 3/3] kvm: x86: Advertise FLUSH_L1D to user space Emanuele Giuseppe Esposito
2023-03-14 13:29 ` [PATCH 0/3] KVM: support the cpu feature FLUSH_L1D Paolo Bonzini
2023-03-20 16:52 ` Jim Mattson
2023-03-21 8:40 ` Emanuele Giuseppe Esposito [this message]
2023-03-21 9:43 ` Paolo Bonzini
2023-03-21 18:30 ` Jim Mattson
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