Re: [PATCH v3] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

2020-07-08 Thread Abhishek Bhardwaj
On Mon, Jul 6, 2020 at 8:14 AM Waiman Long wrote: > > On 7/5/20 5:51 PM, Abhishek Bhardwaj wrote: > > That is why I said a comment will have to be added to highlight this > dependency. For instance, > > +/* > + * Three of the enums are explicitly assigned as the KVM_VMENTRY_L1D_FLUSH > + * config

Re: [PATCH v3] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

2020-07-05 Thread Abhishek Bhardwaj
On Sun, Jul 5, 2020 at 11:48 AM Waiman Long wrote: > > On 7/5/20 2:22 PM, Abhishek Bhardwaj wrote: > > On Sun, Jul 5, 2020 at 8:57 AM Waiman Long wrote: > >> On 7/5/20 11:23 AM, Mike Rapoport wrote: > Nothing prevents people from continuing to use the command line > options if they want

Re: [PATCH v3] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

2020-07-05 Thread Waiman Long
On 7/5/20 2:22 PM, Abhishek Bhardwaj wrote: On Sun, Jul 5, 2020 at 8:57 AM Waiman Long wrote: On 7/5/20 11:23 AM, Mike Rapoport wrote: Nothing prevents people from continuing to use the command line options if they want, right? This just allows a different default. So if a distro is security

Re: [PATCH v3] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

2020-07-05 Thread Abhishek Bhardwaj
On Sun, Jul 5, 2020 at 8:57 AM Waiman Long wrote: > > On 7/5/20 11:23 AM, Mike Rapoport wrote: > >> Nothing prevents people from continuing to use the command line > >> options if they want, right? This just allows a different default. > >> So if a distro is security focused and decided that it w

Re: [PATCH v3] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

2020-07-05 Thread Doug Anderson
Hi, On Sun, Jul 5, 2020 at 8:23 AM Mike Rapoport wrote: > > On Fri, Jul 03, 2020 at 07:00:11AM -0700, Doug Anderson wrote: > > Hi, > > > > On Fri, Jul 3, 2020 at 4:40 AM Mike Rapoport wrote: > > > > > > On Thu, Jul 02, 2020 at 11:43:47PM -0700, Abhishek Bhardwaj wrote: > > > > We have tried to s

Re: [PATCH v3] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

2020-07-05 Thread Waiman Long
On 7/5/20 11:23 AM, Mike Rapoport wrote: Nothing prevents people from continuing to use the command line options if they want, right? This just allows a different default. So if a distro is security focused and decided that it wanted a slower / more secure default then it could ship that way but

Re: [PATCH v3] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

2020-07-05 Thread Mike Rapoport
On Fri, Jul 03, 2020 at 07:00:11AM -0700, Doug Anderson wrote: > Hi, > > On Fri, Jul 3, 2020 at 4:40 AM Mike Rapoport wrote: > > > > On Thu, Jul 02, 2020 at 11:43:47PM -0700, Abhishek Bhardwaj wrote: > > > We have tried to steer away from kernel command line args for a few > > > reasons. > > > >

Re: [PATCH v3] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

2020-07-03 Thread kernel test robot
Hi Abhishek, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on tip/auto-latest] [also build test WARNING on linux/master tip/x86/core kvm/linux-next linus/master v5.8-rc3 next-20200703] [If your patch is applied to the wrong git tree, kindly drop us a note. And w

Re: [PATCH v3] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

2020-07-03 Thread Doug Anderson
Hi, On Fri, Jul 3, 2020 at 4:40 AM Mike Rapoport wrote: > > On Thu, Jul 02, 2020 at 11:43:47PM -0700, Abhishek Bhardwaj wrote: > > We have tried to steer away from kernel command line args for a few reasons. > > > > I am paraphrasing my colleague Doug's argument here (CC'ed him as well) - > > > >

Re: [PATCH v3] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

2020-07-03 Thread Mike Rapoport
On Thu, Jul 02, 2020 at 11:43:47PM -0700, Abhishek Bhardwaj wrote: > We have tried to steer away from kernel command line args for a few reasons. > > I am paraphrasing my colleague Doug's argument here (CC'ed him as well) - > > - The command line args are getting unwieldy. Kernel command line > p

Re: [PATCH v3] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

2020-07-02 Thread Abhishek Bhardwaj
We have tried to steer away from kernel command line args for a few reasons. I am paraphrasing my colleague Doug's argument here (CC'ed him as well) - - The command line args are getting unwieldy. Kernel command line parameters are not a scalable way to set kernel config. It's intended as a super

Re: [PATCH v3] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

2020-07-02 Thread Anthony Steinhauser
Yes, this probably requires an explanation why the change is necessary or useful. Without that it is difficult to give some meaningful feedback.

Re: [PATCH v3] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

2020-07-02 Thread Waiman Long
On 7/2/20 6:12 PM, Abhishek Bhardwaj wrote: This change adds a new kernel configuration that sets the l1d cache flush setting at compile time rather than at run time. Signed-off-by: Abhishek Bhardwaj Can you explain in the commit log why you need a compile time option whereas the desired mit

Re: [PATCH v3] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

2020-07-02 Thread Randy Dunlap
On 7/2/20 3:12 PM, Abhishek Bhardwaj wrote: > This change adds a new kernel configuration that sets the l1d cache > flush setting at compile time rather than at run time. > > Signed-off-by: Abhishek Bhardwaj > > --- > > Changes in v3: > - Change depends on to only x86_64. > - Remove copy paste

[PATCH v3] x86/speculation/l1tf: Add KConfig for setting the L1D cache flush mode

2020-07-02 Thread Abhishek Bhardwaj
This change adds a new kernel configuration that sets the l1d cache flush setting at compile time rather than at run time. Signed-off-by: Abhishek Bhardwaj --- Changes in v3: - Change depends on to only x86_64. - Remove copy paste errors at the end of the KConfig. Changes in v2: - Fix typo in