Re: [Xen-devel] [PATCH 5/7] xen/arm32: Invalidate BTB on guest exit for Cortex A17 and 12

2018-01-31 Thread Stefano Stabellini
On Wed, 31 Jan 2018, Julien Grall wrote: > Hi Stefano, > > On 25/01/18 19:35, Stefano Stabellini wrote: > > > This means that bne will branch only when bit 2 is set. So the only way to > > > end > > > here is because the first 3-bit are equal to 0x00X. This corresponds to > > > IRQ/FIQ vector. >

Re: [Xen-devel] [PATCH 5/7] xen/arm32: Invalidate BTB on guest exit for Cortex A17 and 12

2018-01-25 Thread Stefano Stabellini
On Thu, 25 Jan 2018, Julien Grall wrote: > Hi Stefano, > > On 25/01/18 01:02, Stefano Stabellini wrote: > > On Fri, 19 Jan 2018, Julien Grall wrote: > > > In order to avoid aliasing attackes agains the branch predictor, let's > > > invalidate the BTB on guest exist. This is made complicated by

Re: [Xen-devel] [PATCH 5/7] xen/arm32: Invalidate BTB on guest exit for Cortex A17 and 12

2018-01-25 Thread Julien Grall
Hi Stefano, On 25/01/18 01:02, Stefano Stabellini wrote: On Fri, 19 Jan 2018, Julien Grall wrote: In order to avoid aliasing attackes agains the branch predictor, let's invalidate the BTB on guest exist. This is made complicated by the fact that we cannot take a branch invalidating the BTB.

Re: [Xen-devel] [PATCH 5/7] xen/arm32: Invalidate BTB on guest exit for Cortex A17 and 12

2018-01-24 Thread Stefano Stabellini
On Fri, 19 Jan 2018, Julien Grall wrote: > In order to avoid aliasing attackes agains the branch predictor, let's > invalidate the BTB on guest exist. This is made complicated by the fact > that we cannot take a branch invalidating the BTB. > > This is based on the first version posrted by Marc

Re: [Xen-devel] [PATCH 5/7] xen/arm32: Invalidate BTB on guest exit for Cortex A17 and 12

2018-01-24 Thread Julien Grall
On 24 January 2018 at 22:22, Konrad Rzeszutek Wilk wrote: > On Fri, Jan 19, 2018 at 01:41:01PM +, Julien Grall wrote: >> In order to avoid aliasing attackes agains the branch predictor, let's >> invalidate the BTB on guest exist. This is made complicated by the fact >>

Re: [Xen-devel] [PATCH 5/7] xen/arm32: Invalidate BTB on guest exit for Cortex A17 and 12

2018-01-24 Thread Konrad Rzeszutek Wilk
On Fri, Jan 19, 2018 at 01:41:01PM +, Julien Grall wrote: > In order to avoid aliasing attackes agains the branch predictor, let's > invalidate the BTB on guest exist. This is made complicated by the fact > that we cannot take a branch invalidating the BTB. > > This is based on the first