Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

>>> On 23.01.18 at 18:33, wrote: > Well at very least there should be something in the boot scrool that > says, "Enabling Xen Pagetable protection (XPTI) for PV guests" or > something. (That goes for the current round of XPTI as well really.) And indeed I have this on

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 01/23/2018 04:56 PM, Juergen Gross wrote: > On 23/01/18 17:45, George Dunlap wrote: >> On 01/22/2018 06:39 PM, Andrew Cooper wrote: >>> Juergen: you're now adding a LTR into the context switch path which >>> tends to be very slow.  I.e. As currently presented, this series >>> necessarily has a

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 23/01/18 17:45, George Dunlap wrote: > On 01/22/2018 06:39 PM, Andrew Cooper wrote: >> Juergen: you're now adding a LTR into the context switch path which >> tends to be very slow.  I.e. As currently presented, this series >> necessarily has a higher runtime overhead than Jan's XPTI. > > So

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 01/22/2018 06:39 PM, Andrew Cooper wrote: > On 22/01/18 16:51, Jan Beulich wrote: > On 22.01.18 at 16:00, wrote: >>> On 22/01/18 15:48, Jan Beulich wrote: >>> On 22.01.18 at 15:38, wrote: > On 22/01/18 15:22, Jan Beulich wrote: > On

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 23/01/18 12:45, Andrew Cooper wrote: > On 23/01/18 10:10, Juergen Gross wrote: >> On 23/01/18 10:31, Jan Beulich wrote: >> On 23.01.18 at 10:24, wrote: On 23/01/18 09:53, Jan Beulich wrote: On 23.01.18 at 07:34, wrote: >> On 22/01/18

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 Hey, Hi! On Mon, 2018-01-22 at 18:39 +, Andrew Cooper wrote: > > > > On 22.01.18 at 15:38, wrote: > > > I'm quite sure the performance will be much better as it doesn't > > > require > > > per physical cpu L4 page tables, but

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 23/01/18 10:10, Juergen Gross wrote: > On 23/01/18 10:31, Jan Beulich wrote: > On 23.01.18 at 10:24, wrote: >>> On 23/01/18 09:53, Jan Beulich wrote: >>> On 23.01.18 at 07:34, wrote: > On 22/01/18 19:39, Andrew Cooper wrote: >> One of my

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 23/01/18 08:36, Jan Beulich wrote: On 22.01.18 at 20:02, wrote: >> On 22/01/18 18:48, George Dunlap wrote: >>> On 01/22/2018 06:39 PM, Andrew Cooper wrote: Jan: As to the things not covered by the current XPTI, hiding most of the .text section is

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 01/22/2018 07:02 PM, Andrew Cooper wrote: > On 22/01/18 18:48, George Dunlap wrote: >> On 01/22/2018 06:39 PM, Andrew Cooper wrote: >>> On 22/01/18 16:51, Jan Beulich wrote: >>> On 22.01.18 at 16:00, wrote: > On 22/01/18 15:48, Jan Beulich wrote: > On 22.01.18

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 23/01/18 10:31, Jan Beulich wrote: On 23.01.18 at 10:24, wrote: >> On 23/01/18 09:53, Jan Beulich wrote: >> On 23.01.18 at 07:34, wrote: On 22/01/18 19:39, Andrew Cooper wrote: > One of my concerns is that this patch series moves further

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 23/01/18 09:40, Jan Beulich wrote: On 23.01.18 at 06:50, wrote: >> On 22/01/18 17:51, Jan Beulich wrote: >>> But isn't that model having the same synchronization issues upon >>> guest L4 updates which Andrew was fighting with? >> >> I don't think so, as the number of

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 23/01/18 09:53, Jan Beulich wrote: On 23.01.18 at 07:34, wrote: >> On 22/01/18 19:39, Andrew Cooper wrote: >>> One of my concerns is that this patch series moves further away from the >>> secondary goal of my KAISER series, which was to have the IDT and GDT >>> mapped at

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

>>> On 23.01.18 at 06:50, wrote: > On 22/01/18 17:51, Jan Beulich wrote: >> But isn't that model having the same synchronization issues upon >> guest L4 updates which Andrew was fighting with? > > I don't think so, as the number of shadows will always only be max. 1 > with my

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

>>> On 22.01.18 at 20:02, wrote: > On 22/01/18 18:48, George Dunlap wrote: >> On 01/22/2018 06:39 PM, Andrew Cooper wrote: >>> Jan: As to the things not covered by the current XPTI, hiding most of >>> the .text section is important to prevent fingerprinting or ROP >>>

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 23/01/18 07:34, Juergen Gross wrote: > On 22/01/18 19:39, Andrew Cooper wrote: >> On 22/01/18 16:51, Jan Beulich wrote: >> On 22.01.18 at 16:00, wrote: On 22/01/18 15:48, Jan Beulich wrote: On 22.01.18 at 15:38, wrote: >> On 22/01/18

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 22/01/18 22:45, Konrad Rzeszutek Wilk wrote: > On Mon, Jan 22, 2018 at 01:32:44PM +0100, Juergen Gross wrote: >> As a preparation for doing page table isolation in the Xen hypervisor >> in order to mitigate "Meltdown" use dedicated stacks, GDT and TSS for >> 64 bit PV domains mapped to the

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 22/01/18 19:39, Andrew Cooper wrote: > On 22/01/18 16:51, Jan Beulich wrote: > On 22.01.18 at 16:00, wrote: >>> On 22/01/18 15:48, Jan Beulich wrote: >>> On 22.01.18 at 15:38, wrote: > On 22/01/18 15:22, Jan Beulich wrote: > On 22.01.18 at

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 22/01/18 17:51, Jan Beulich wrote: On 22.01.18 at 16:00, wrote: >> On 22/01/18 15:48, Jan Beulich wrote: >> On 22.01.18 at 15:38, wrote: On 22/01/18 15:22, Jan Beulich wrote: On 22.01.18 at 15:18, wrote: >> On

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 22/01/18 18:48, George Dunlap wrote: > On 01/22/2018 06:39 PM, Andrew Cooper wrote: >> On 22/01/18 16:51, Jan Beulich wrote: >> On 22.01.18 at 16:00, wrote: On 22/01/18 15:48, Jan Beulich wrote: On 22.01.18 at 15:38, wrote: >> On

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 01/22/2018 06:39 PM, Andrew Cooper wrote: > On 22/01/18 16:51, Jan Beulich wrote: > On 22.01.18 at 16:00, wrote: >>> On 22/01/18 15:48, Jan Beulich wrote: >>> On 22.01.18 at 15:38, wrote: > On 22/01/18 15:22, Jan Beulich wrote: > On

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 22/01/18 16:51, Jan Beulich wrote: On 22.01.18 at 16:00, wrote: >> On 22/01/18 15:48, Jan Beulich wrote: >> On 22.01.18 at 15:38, wrote: On 22/01/18 15:22, Jan Beulich wrote: On 22.01.18 at 15:18, wrote: >> On

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

>>> On 22.01.18 at 16:00, wrote: > On 22/01/18 15:48, Jan Beulich wrote: > On 22.01.18 at 15:38, wrote: >>> On 22/01/18 15:22, Jan Beulich wrote: >>> On 22.01.18 at 15:18, wrote: > On 22/01/18 13:50, Jan Beulich wrote: > On

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 22/01/18 15:48, Jan Beulich wrote: On 22.01.18 at 15:38, wrote: >> On 22/01/18 15:22, Jan Beulich wrote: >> On 22.01.18 at 15:18, wrote: On 22/01/18 13:50, Jan Beulich wrote: On 22.01.18 at 13:32, wrote: >> As a

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

>>> On 22.01.18 at 15:38, wrote: > On 22/01/18 15:22, Jan Beulich wrote: > On 22.01.18 at 15:18, wrote: >>> On 22/01/18 13:50, Jan Beulich wrote: >>> On 22.01.18 at 13:32, wrote: > As a preparation for doing page table isolation in

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

On 22/01/18 15:22, Jan Beulich wrote: On 22.01.18 at 15:18, wrote: >> On 22/01/18 13:50, Jan Beulich wrote: >> On 22.01.18 at 13:32, wrote: As a preparation for doing page table isolation in the Xen hypervisor in order to mitigate "Meltdown"

Re: [Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

>>> On 22.01.18 at 13:32, wrote: > As a preparation for doing page table isolation in the Xen hypervisor > in order to mitigate "Meltdown" use dedicated stacks, GDT and TSS for > 64 bit PV domains mapped to the per-domain virtual area. > > The per-vcpu stacks are used for early

[Xen-devel] [PATCH RFC v2 00/12] xen/x86: use per-vcpu stacks for 64 bit pv domains

As a preparation for doing page table isolation in the Xen hypervisor in order to mitigate "Meltdown" use dedicated stacks, GDT and TSS for 64 bit PV domains mapped to the per-domain virtual area. The per-vcpu stacks are used for early interrupt handling only. After saving the domain's registers