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Re: [PATCH v3 14/22] microvm: use 2G split unconditionally
From: |
Igor Mammedov |
Subject: |
Re: [PATCH v3 14/22] microvm: use 2G split unconditionally |
Date: |
Wed, 27 May 2020 16:35:07 +0200 |
On Wed, 27 May 2020 16:26:46 +0200
Igor Mammedov <address@hidden> wrote:
> On Wed, 27 May 2020 15:06:28 +0200
> Paolo Bonzini <address@hidden> wrote:
>
> > On 27/05/20 14:25, Igor Mammedov wrote:
> > >> (2) we loose a gigabyte page.
> > > I'm not sure waht exactly we loose in this case.
> > > Lets assume we allocating guest 5G of continuous RAM using 1G
> > > huge pages,
> > > in this case I'd think that on host side MMIO overlay won't
> > > affect RAM blob
> > > on guest side pagetables will be fragmented due to MMIO holes,
> > > but guest still
> > > could use huge pages smaller ones in fragmented area and 1G
> > > where there is no fragmentation.
> >
> > Access to the 3G-4G area would not be able to use 1G EPT pages.
> Could it use 2Mb pages instead of 1Gb?
> Do we really care about 1 gigabyte huge page in microvm intended usecase?
> (fast starting VMs for microservices like FaaS, which unlikely would use much
> memory to begin with)
my interest in having single memory region, is in possibility of drop in
conversion to [nv|pc-dimm] later on
without breaking ABI. (I'm not sure that we actually need it though)
> > But why use 2G split instead of 3G? There's only very little MMIO and
> > no PCI hole (including no huge MMCONFIG BAR) on microvm.
> >
> > Paolo
> >
>
>
- [PATCH v3 14/22] microvm: use 2G split unconditionally, (continued)
- [PATCH v3 14/22] microvm: use 2G split unconditionally, Gerd Hoffmann, 2020/05/20
- Re: [PATCH v3 14/22] microvm: use 2G split unconditionally, Philippe Mathieu-Daudé, 2020/05/20
- Re: [PATCH v3 14/22] microvm: use 2G split unconditionally, Igor Mammedov, 2020/05/21
- Re: [PATCH v3 14/22] microvm: use 2G split unconditionally, Igor Mammedov, 2020/05/21
- Re: [PATCH v3 14/22] microvm: use 2G split unconditionally, Gerd Hoffmann, 2020/05/25
- Re: [PATCH v3 14/22] microvm: use 2G split unconditionally, Igor Mammedov, 2020/05/25
- Re: [PATCH v3 14/22] microvm: use 2G split unconditionally, Gerd Hoffmann, 2020/05/26
- Re: [PATCH v3 14/22] microvm: use 2G split unconditionally, Igor Mammedov, 2020/05/27
- Re: [PATCH v3 14/22] microvm: use 2G split unconditionally, Paolo Bonzini, 2020/05/27
- Re: [PATCH v3 14/22] microvm: use 2G split unconditionally, Igor Mammedov, 2020/05/27
- Re: [PATCH v3 14/22] microvm: use 2G split unconditionally,
Igor Mammedov <=
- Re: [PATCH v3 14/22] microvm: use 2G split unconditionally, Paolo Bonzini, 2020/05/27
- Re: [PATCH v3 14/22] microvm: use 2G split unconditionally, Gerd Hoffmann, 2020/05/28
- Re: [PATCH v3 14/22] microvm: use 2G split unconditionally, Gerd Hoffmann, 2020/05/28
[PATCH v3 13/22] x86: coldplug cpus, Gerd Hoffmann, 2020/05/20
[PATCH v3 04/22] [testing] seabios: update binaries to master snapshot, Gerd Hoffmann, 2020/05/20
Re: [PATCH v3 00/22] microvm: add acpi support, no-reply, 2020/05/20
Re: [PATCH v3 00/22] microvm: add acpi support, no-reply, 2020/05/20
Re: [PATCH v3 00/22] microvm: add acpi support, no-reply, 2020/05/20
Re: [PATCH v3 00/22] microvm: add acpi support, no-reply, 2020/05/20