Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

On Fri, Feb 16, 2018 at 12:51 AM, Nadav Amit wrote: > Andrew Cooper wrote: > >> On 16/02/2018 00:25, Nadav Amit wrote: >>> Dave Hansen wrote: >>> On 02/15/2018 08:35 AM, Nadav Amit wrote: > I removed the PTI

Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

On Fri, Feb 16, 2018 at 12:51 AM, Nadav Amit wrote: > Andrew Cooper wrote: > >> On 16/02/2018 00:25, Nadav Amit wrote: >>> Dave Hansen wrote: >>> On 02/15/2018 08:35 AM, Nadav Amit wrote: > I removed the PTI disabling while SMEP is unsupported, although I > must admit I did not

Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

On 16/02/2018 00:51, Nadav Amit wrote: > Andrew Cooper wrote: > >> On 16/02/2018 00:25, Nadav Amit wrote: >>> Dave Hansen wrote: >>> On 02/15/2018 08:35 AM, Nadav Amit wrote: > I removed the PTI disabling while SMEP is unsupported,

Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

On 16/02/2018 00:51, Nadav Amit wrote: > Andrew Cooper wrote: > >> On 16/02/2018 00:25, Nadav Amit wrote: >>> Dave Hansen wrote: >>> On 02/15/2018 08:35 AM, Nadav Amit wrote: > I removed the PTI disabling while SMEP is unsupported, although I > must admit I did not fully understand

Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

Andrew Cooper wrote: > On 16/02/2018 00:25, Nadav Amit wrote: >> Dave Hansen wrote: >> >>> On 02/15/2018 08:35 AM, Nadav Amit wrote: I removed the PTI disabling while SMEP is unsupported, although I must admit I did not fully

Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

Andrew Cooper wrote: > On 16/02/2018 00:25, Nadav Amit wrote: >> Dave Hansen wrote: >> >>> On 02/15/2018 08:35 AM, Nadav Amit wrote: I removed the PTI disabling while SMEP is unsupported, although I must admit I did not fully understand why it is required. >>> Do you mean you don't

Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

Dave Hansen wrote: > On 02/15/2018 04:25 PM, Nadav Amit wrote: >> Dave Hansen wrote: >> >>> On 02/15/2018 08:35 AM, Nadav Amit wrote: I removed the PTI disabling while SMEP is unsupported, although I must admit I did not fully

Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

Dave Hansen wrote: > On 02/15/2018 04:25 PM, Nadav Amit wrote: >> Dave Hansen wrote: >> >>> On 02/15/2018 08:35 AM, Nadav Amit wrote: I removed the PTI disabling while SMEP is unsupported, although I must admit I did not fully understand why it is required. >>> >>> Do you mean you

Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

On 16/02/2018 00:25, Nadav Amit wrote: > Dave Hansen wrote: > >> On 02/15/2018 08:35 AM, Nadav Amit wrote: >>> I removed the PTI disabling while SMEP is unsupported, although I >>> must admit I did not fully understand why it is required. >> Do you mean you don't

Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

On 16/02/2018 00:25, Nadav Amit wrote: > Dave Hansen wrote: > >> On 02/15/2018 08:35 AM, Nadav Amit wrote: >>> I removed the PTI disabling while SMEP is unsupported, although I >>> must admit I did not fully understand why it is required. >> Do you mean you don't fully understand how PTI gives

Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

On 02/15/2018 04:25 PM, Nadav Amit wrote: > Dave Hansen wrote: > >> On 02/15/2018 08:35 AM, Nadav Amit wrote: >>> I removed the PTI disabling while SMEP is unsupported, although I >>> must admit I did not fully understand why it is required. >> >> Do you mean you

Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

On 02/15/2018 04:25 PM, Nadav Amit wrote: > Dave Hansen wrote: > >> On 02/15/2018 08:35 AM, Nadav Amit wrote: >>> I removed the PTI disabling while SMEP is unsupported, although I >>> must admit I did not fully understand why it is required. >> >> Do you mean you don't fully understand how PTI

Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

Dave Hansen wrote: > On 02/15/2018 08:35 AM, Nadav Amit wrote: >> I removed the PTI disabling while SMEP is unsupported, although I >> must admit I did not fully understand why it is required. > > Do you mean you don't fully understand how PTI gives SMEP-like

Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

Dave Hansen wrote: > On 02/15/2018 08:35 AM, Nadav Amit wrote: >> I removed the PTI disabling while SMEP is unsupported, although I >> must admit I did not fully understand why it is required. > > Do you mean you don't fully understand how PTI gives SMEP-like behavior > on non-SMEP hardware?

Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

On 02/15/2018 08:35 AM, Nadav Amit wrote: > I removed the PTI disabling while SMEP is unsupported, although I > must admit I did not fully understand why it is required. Do you mean you don't fully understand how PTI gives SMEP-like behavior on non-SMEP hardware?

Re: [PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

On 02/15/2018 08:35 AM, Nadav Amit wrote: > I removed the PTI disabling while SMEP is unsupported, although I > must admit I did not fully understand why it is required. Do you mean you don't fully understand how PTI gives SMEP-like behavior on non-SMEP hardware?

[PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

Compatibility mode should be safe of Meltdown, since the pointers are only 32-bit long. This can allow us to disable PTI selectively as long as x86-32 processes are running and to enable global pages throughout this time. These patches may also be a basis for later disabling PTI selectively for

[PATCH RFC v2 0/6] x86: Disabling PTI in compatibility mode

Compatibility mode should be safe of Meltdown, since the pointers are only 32-bit long. This can allow us to disable PTI selectively as long as x86-32 processes are running and to enable global pages throughout this time. These patches may also be a basis for later disabling PTI selectively for