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From: Peter Zijlstra <peterz@infradead.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: Liran Alon <liran.alon@oracle.com>,
Alexandre Chartre <alexandre.chartre@oracle.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Radim Krcmar <rkrcmar@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
kvm list <kvm@vger.kernel.org>, X86 ML <x86@kernel.org>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
jan.setjeeilers@oracle.com, Jonathan Adams <jwadams@google.com>
Subject: Re: [RFC KVM 00/27] KVM Address Space Isolation
Date: Tue, 14 May 2019 09:37:38 +0200 [thread overview]
Message-ID: <20190514073738.GH2589@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CALCETrXK8+tUxNA=iVDse31nFRZyiQYvcrQxV1JaidhnL4GC0w@mail.gmail.com>
On Mon, May 13, 2019 at 07:07:36PM -0700, Andy Lutomirski wrote:
> On Mon, May 13, 2019 at 2:09 PM Liran Alon <liran.alon@oracle.com> wrote:
> > The hope is that the very vast majority of #VMExit handlers will be
> > able to completely run without requiring to switch to full address
> > space. Therefore, avoiding the performance hit of (2).
> > However, for the very few #VMExits that does require to run in full
> > kernel address space, we must first kick the sibling hyperthread
> > outside of guest and only then switch to full kernel address space
> > and only once all hyperthreads return to KVM address space, then
> > allow then to enter into guest.
>
> What exactly does "kick" mean in this context? It sounds like you're
> going to need to be able to kick sibling VMs from extremely atomic
> contexts like NMI and MCE.
Yeah, doing the full synchronous thing from NMI/MCE context sounds
exceedingly dodgy, howver..
Realistically they only need to send an IPI to the other sibling; they
don't need to wait for the VMExit to complete or anything else.
And that is something we can do from NMI context -- with a bit of care.
See also arch_irq_work_raise(); specifically we need to ensure we leave
the APIC in an idle state, such that if we interrupted an APIC sequence
it will not suddenly fail/violate the APIC write/state etc.
next prev parent reply other threads:[~2019-05-14 7:37 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-13 14:38 [RFC KVM 00/27] KVM Address Space Isolation Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 01/27] kernel: Export memory-management symbols required for KVM address space isolation Alexandre Chartre
2019-05-13 15:15 ` Peter Zijlstra
2019-05-13 15:17 ` Liran Alon
2019-05-13 14:38 ` [RFC KVM 02/27] KVM: x86: Introduce address_space_isolation module parameter Alexandre Chartre
2019-05-13 15:46 ` Andy Lutomirski
2019-05-13 15:55 ` Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 03/27] KVM: x86: Introduce KVM separate virtual address space Alexandre Chartre
2019-05-13 15:45 ` Andy Lutomirski
2019-05-13 16:04 ` Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 04/27] KVM: x86: Switch to KVM address space on entry to guest Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 05/27] KVM: x86: Add handler to exit kvm isolation Alexandre Chartre
2019-05-13 15:49 ` Andy Lutomirski
2019-05-13 16:10 ` Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 06/27] KVM: x86: Exit KVM isolation on IRQ entry Alexandre Chartre
2019-05-13 15:51 ` Andy Lutomirski
2019-05-13 16:28 ` Alexandre Chartre
2019-05-13 18:13 ` Andy Lutomirski
2019-05-14 7:07 ` Peter Zijlstra
2019-05-14 7:58 ` Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 07/27] KVM: x86: Switch to host address space when may access sensitive data Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 08/27] KVM: x86: Optimize branches which checks if address space isolation enabled Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 09/27] kvm/isolation: function to track buffers allocated for the KVM page table Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 10/27] kvm/isolation: add KVM page table entry free functions Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 11/27] kvm/isolation: add KVM page table entry offset functions Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 12/27] kvm/isolation: add KVM page table entry allocation functions Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 13/27] kvm/isolation: add KVM page table entry set functions Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 14/27] kvm/isolation: functions to copy page table entries for a VA range Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 15/27] kvm/isolation: keep track of VA range mapped in KVM address space Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 16/27] kvm/isolation: functions to clear page table entries for a VA range Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 17/27] kvm/isolation: improve mapping copy when mapping is already present Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 18/27] kvm/isolation: function to copy page table entries for percpu buffer Alexandre Chartre
2019-05-13 18:18 ` Andy Lutomirski
2019-05-14 7:09 ` Peter Zijlstra
2019-05-14 8:25 ` Alexandre Chartre
2019-05-14 8:34 ` Andy Lutomirski
2019-05-14 9:41 ` Alexandre Chartre
2019-05-14 15:23 ` Andy Lutomirski
2019-05-14 16:24 ` Alexandre Chartre
2019-05-14 17:05 ` Peter Zijlstra
2019-05-14 18:09 ` Sean Christopherson
2019-05-14 20:33 ` Andy Lutomirski
2019-05-14 21:06 ` Sean Christopherson
2019-05-14 21:55 ` Andy Lutomirski
2019-05-14 22:38 ` Sean Christopherson
2019-05-18 0:05 ` Jonathan Adams
2019-05-14 20:27 ` Andy Lutomirski
2019-05-13 14:38 ` [RFC KVM 19/27] kvm/isolation: initialize the KVM page table with core mappings Alexandre Chartre
2019-05-13 15:50 ` Dave Hansen
2019-05-13 16:00 ` Andy Lutomirski
2019-05-13 17:00 ` Alexandre Chartre
2019-05-13 16:46 ` Sean Christopherson
2019-05-13 16:47 ` Alexandre Chartre
2019-05-14 10:26 ` Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 20/27] kvm/isolation: initialize the KVM page table with vmx specific data Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 21/27] kvm/isolation: initialize the KVM page table with vmx VM data Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 22/27] kvm/isolation: initialize the KVM page table with vmx cpu data Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 23/27] kvm/isolation: initialize the KVM page table with the vcpu tasks Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 24/27] kvm/isolation: KVM page fault handler Alexandre Chartre
2019-05-13 15:15 ` Peter Zijlstra
2019-05-13 21:25 ` Liran Alon
2019-05-14 2:02 ` Andy Lutomirski
2019-05-14 7:21 ` Peter Zijlstra
2019-05-14 15:36 ` Alexandre Chartre
2019-05-14 15:43 ` Andy Lutomirski
2019-05-13 16:02 ` Andy Lutomirski
2019-05-13 16:21 ` Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 25/27] kvm/isolation: implement actual KVM isolation enter/exit Alexandre Chartre
2019-05-13 15:16 ` Peter Zijlstra
2019-05-13 16:01 ` Andy Lutomirski
2019-05-13 14:38 ` [RFC KVM 26/27] kvm/isolation: initialize the KVM page table with KVM memslots Alexandre Chartre
2019-05-13 14:38 ` [RFC KVM 27/27] kvm/isolation: initialize the KVM page table with KVM buses Alexandre Chartre
2019-05-13 16:42 ` [RFC KVM 00/27] KVM Address Space Isolation Liran Alon
2019-05-13 18:17 ` Andy Lutomirski
2019-05-13 21:08 ` Liran Alon
2019-05-14 2:07 ` Andy Lutomirski
2019-05-14 7:37 ` Peter Zijlstra [this message]
2019-05-14 21:32 ` Jan Setje-Eilers
2019-05-14 8:05 ` Liran Alon
2019-05-14 7:29 ` Peter Zijlstra
2019-05-14 7:57 ` Liran Alon
2019-05-14 8:33 ` Alexandre Chartre
2019-05-13 19:31 ` Nakajima, Jun
2019-05-13 21:16 ` Liran Alon
[not found] ` <D07C8F51-F2DF-4C8B-AB3B-0DFABD5F4C33@intel.com>
2019-05-13 21:53 ` Liran Alon
2019-05-15 12:52 ` Alexandre Chartre
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