From: Patrick Roy <roypat@amazon.co.uk>
To: David Hildenbrand <david@redhat.com>, <tabba@google.com>,
<quic_eberman@quicinc.com>, <seanjc@google.com>,
<pbonzini@redhat.com>, <jthoughton@google.com>,
<ackerleytng@google.com>, <vannapurve@google.com>,
<rppt@kernel.org>
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<kalyazin@amazon.com>, <xmarcalx@amazon.com>,
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Subject: Re: [RFC PATCH v3 0/6] Direct Map Removal for guest_memfd
Date: Fri, 15 Nov 2024 17:23:47 +0000 [thread overview]
Message-ID: <81d14448-29eb-4496-b876-ef6de526a840@amazon.co.uk> (raw)
In-Reply-To: <dcdce8e1-51da-42da-a892-59c6ccd9de23@redhat.com>
On Fri, 2024-11-15 at 17:10 +0000, David Hildenbrand wrote:
>> [...]
>>
>> I've talked to Fares internally, and it seems that generally doing
>> mm-local mappings of guest memory would work for us. We also figured out
>> what the "interrupt problem" is, namely that if we receive an interrupt
>> while executing in a context that has mm-local mappings available, those
>> mappings will continue to be available while the interrupt is being
>> handled.
>
> Isn't that likely also the case with secretmem where we removed the
> directmap, but have an effective per-mm mapping in the (user-space
> portion) of the page table?
Mh, that's an excellent point, I never thought of that. But with
secretmem, the memory would still be protected by SMAP (admittedly, I
have no idea how much this is worth in the face of all these speculative
issues), right?
>> I'm talking to my security folks to see how much of a concern
>> this is for the speculation hardening we're trying to achieve. Will keep
>> you in the loop there :)
>
> Thanks!
>
> --
> Cheers,
>
> David / dhildenb
Best,
Patrick
prev parent reply other threads:[~2024-11-15 17:24 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-30 13:49 Patrick Roy
2024-10-30 13:49 ` [RFC PATCH v3 1/6] arch: introduce set_direct_map_valid_noflush() Patrick Roy
2024-10-31 9:57 ` David Hildenbrand
2024-11-11 12:12 ` Vlastimil Babka
2024-11-12 14:48 ` Patrick Roy
2024-10-30 13:49 ` [RFC PATCH v3 2/6] kvm: gmem: add flag to remove memory from kernel direct map Patrick Roy
2024-10-31 13:56 ` Mike Day
2024-10-30 13:49 ` [RFC PATCH v3 3/6] kvm: gmem: implement direct map manipulation routines Patrick Roy
2024-10-31 14:19 ` Mike Day
2024-10-30 13:49 ` [RFC PATCH v3 4/6] kvm: gmem: add trace point for direct map state changes Patrick Roy
2024-10-30 13:49 ` [RFC PATCH v3 5/6] kvm: document KVM_GMEM_NO_DIRECT_MAP flag Patrick Roy
2024-10-30 13:49 ` [RFC PATCH v3 6/6] kvm: selftests: run gmem tests with KVM_GMEM_NO_DIRECT_MAP set Patrick Roy
2024-10-31 9:50 ` [RFC PATCH v3 0/6] Direct Map Removal for guest_memfd David Hildenbrand
2024-10-31 10:42 ` Patrick Roy
2024-11-01 0:10 ` Manwaring, Derek
2024-11-01 15:18 ` Sean Christopherson
2024-11-01 18:32 ` Kaplan, David
2024-11-01 16:06 ` Dave Hansen
2024-11-01 16:56 ` Manwaring, Derek
2024-11-01 17:20 ` Dave Hansen
2024-11-01 18:31 ` Manwaring, Derek
2024-11-01 18:43 ` Dave Hansen
2024-11-01 19:29 ` Manwaring, Derek
2024-11-01 19:39 ` Dave Hansen
2024-11-04 8:33 ` Reshetova, Elena
2024-11-06 17:04 ` Manwaring, Derek
2024-11-08 10:36 ` Reshetova, Elena
2024-11-13 3:31 ` Manwaring, Derek
2024-11-04 12:18 ` David Hildenbrand
2024-11-04 13:09 ` Patrick Roy
2024-11-04 21:30 ` David Hildenbrand
2024-11-12 14:40 ` Patrick Roy
2024-11-12 14:52 ` David Hildenbrand
2024-11-15 16:59 ` Patrick Roy
2024-11-15 17:10 ` David Hildenbrand
2024-11-15 17:23 ` Patrick Roy [this message]
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