Re: [PATCH 4/4] x86, efi: Map runtime services 1:1

2013-06-10 Thread Borislav Petkov
On Thu, Jun 06, 2013 at 12:38:10PM -0700, H. Peter Anvin wrote: > On 06/06/2013 12:36 PM, Borislav Petkov wrote: > > On Thu, Jun 06, 2013 at 12:28:20PM -0700, H. Peter Anvin wrote: > >> Or we could materialize mappings for this specific PGD. However, > >> adding a read of %cr3 in __do_page_fault so

Re: [PATCH 4/4] x86, efi: Map runtime services 1:1

2013-06-06 Thread H. Peter Anvin
On 06/06/2013 12:36 PM, Borislav Petkov wrote: > On Thu, Jun 06, 2013 at 12:28:20PM -0700, H. Peter Anvin wrote: >> Or we could materialize mappings for this specific PGD. However, >> adding a read of %cr3 in __do_page_fault sounds expensive. > > Yes, I think we want to make sure all mappings are

Re: [PATCH 4/4] x86, efi: Map runtime services 1:1

2013-06-06 Thread Borislav Petkov
On Thu, Jun 06, 2013 at 12:28:20PM -0700, H. Peter Anvin wrote: > Or we could materialize mappings for this specific PGD. However, > adding a read of %cr3 in __do_page_fault sounds expensive. Yes, I think we want to make sure all mappings are there when we do an EFI runtime call so that we never #

Re: [PATCH 4/4] x86, efi: Map runtime services 1:1

2013-06-06 Thread H. Peter Anvin
On 06/06/2013 08:58 AM, Borislav Petkov wrote: > -- > diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c > index 654be4ae3047..7a6129afdff1 100644 > --- a/arch/x86/mm/fault.c > +++ b/arch/x86/mm/fault.c > @@ -1021,6 +1021,9 @@ __do_page_fault(struct pt_regs *regs, unsigned long > error_code) >

Re: [PATCH 4/4] x86, efi: Map runtime services 1:1

2013-06-06 Thread Borislav Petkov
On Thu, Jun 06, 2013 at 03:29:08PM +0200, Borislav Petkov wrote: > On Thu, Jun 06, 2013 at 02:14:39PM +0100, Matt Fleming wrote: > > This patch makes my TunnelMountain machine spin in handle_pte_fault() > > when triggering one of the "firmware makes references to physical > > addresses" code paths.

Re: [PATCH 4/4] x86, efi: Map runtime services 1:1

2013-06-06 Thread Borislav Petkov
On Thu, Jun 06, 2013 at 02:14:39PM +0100, Matt Fleming wrote: > This patch makes my TunnelMountain machine spin in handle_pte_fault() > when triggering one of the "firmware makes references to physical > addresses" code paths. > > I'll try and dig into this tomorrow to figure out what's going on.

Re: [PATCH 4/4] x86, efi: Map runtime services 1:1

2013-06-06 Thread Matt Fleming
On Sun, 02 Jun, at 02:56:10PM, Borislav Petkov wrote: > From: Borislav Petkov > > Due to the braindead design of EFI, we cannot map runtime services more > than once for the duration of a booted system. Thus, if we want to use > EFI runtime services in a kexec'ed kernel, maybe the only possible a