Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-29 Thread Edgecombe, Rick P
On Thu, 2020-10-29 at 10:12 +0200, Mike Rapoport wrote: > This series goal was primarily to separate dependincies and make it > clearer what DEBUG_PAGEALLOC and what SET_DIRECT_MAP are. As it > turned > out, there is also some lack of consistency between architectures > that > implement either of t

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-29 Thread David Hildenbrand
On 25.10.20 11:15, Mike Rapoport wrote: From: Mike Rapoport Hi, During recent discussion about KVM protected memory, David raised a concern about usage of __kernel_map_pages() outside of DEBUG_PAGEALLOC scope [1]. Indeed, for architectures that define CONFIG_ARCH_HAS_SET_DIRECT_MAP it is poss

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-29 Thread Mike Rapoport
On Wed, Oct 28, 2020 at 09:03:31PM +, Edgecombe, Rick P wrote: > > On Wed, Oct 28, 2020 at 11:20:12AM +, Will Deacon wrote: > > > On Tue, Oct 27, 2020 at 10:38:16AM +0200, Mike Rapoport wrote: > > > > > > > > This is a theoretical bug, but i

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-28 Thread Edgecombe, Rick P
On Wed, 2020-10-28 at 13:09 +0200, Mike Rapoport wrote: > On Tue, Oct 27, 2020 at 09:46:35AM +0100, David Hildenbrand wrote: > > On 27.10.20 09:38, Mike Rapoport wrote: > > > On Mon, Oct 26, 2020 at 06:05:30PM +, Edgecombe, Rick P > > > wrote: > > > > > > > Beyond whatever you are seeing, for

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-28 Thread Will Deacon
On Tue, Oct 27, 2020 at 10:38:16AM +0200, Mike Rapoport wrote: > On Mon, Oct 26, 2020 at 06:05:30PM +, Edgecombe, Rick P wrote: > > On Mon, 2020-10-26 at 11:05 +0200, Mike Rapoport wrote: > > > On Mon, Oct 26, 2020 at 01:13:52AM +, Edgecombe, Rick P wrote: > > > > On Sun, 2020-10-25 at 12:1

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-28 Thread Mike Rapoport
On Wed, Oct 28, 2020 at 12:17:35PM +0100, David Hildenbrand wrote: > On 28.10.20 12:09, Mike Rapoport wrote: > > On Tue, Oct 27, 2020 at 09:46:35AM +0100, David Hildenbrand wrote: > > > On 27.10.20 09:38, Mike Rapoport wrote: > > > > On Mon, Oct 26, 2020 at 06:05:30PM +, Edgecombe, Rick P wrote

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-28 Thread Mike Rapoport
On Wed, Oct 28, 2020 at 11:20:12AM +, Will Deacon wrote: > On Tue, Oct 27, 2020 at 10:38:16AM +0200, Mike Rapoport wrote: > > On Mon, Oct 26, 2020 at 06:05:30PM +, Edgecombe, Rick P wrote: > > > On Mon, 2020-10-26 at 11:05 +0200, Mike Rapoport wrote: > > > > On Mon, Oct 26, 2020 at 01:13:52

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-28 Thread David Hildenbrand
On 28.10.20 12:09, Mike Rapoport wrote: On Tue, Oct 27, 2020 at 09:46:35AM +0100, David Hildenbrand wrote: On 27.10.20 09:38, Mike Rapoport wrote: On Mon, Oct 26, 2020 at 06:05:30PM +, Edgecombe, Rick P wrote: Beyond whatever you are seeing, for the latter case of new things getting intro

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-28 Thread Mike Rapoport
On Tue, Oct 27, 2020 at 09:46:35AM +0100, David Hildenbrand wrote: > On 27.10.20 09:38, Mike Rapoport wrote: > > On Mon, Oct 26, 2020 at 06:05:30PM +, Edgecombe, Rick P wrote: > > > > > Beyond whatever you are seeing, for the latter case of new things > > > getting introduced to an interface w

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-28 Thread Edgecombe, Rick P
On Wed, 2020-10-28 at 13:30 +0200, Mike Rapoport wrote: > On Wed, Oct 28, 2020 at 11:20:12AM +, Will Deacon wrote: > > On Tue, Oct 27, 2020 at 10:38:16AM +0200, Mike Rapoport wrote: > > > On Mon, Oct 26, 2020 at 06:05:30PM +, Edgecombe, Rick P > > > wrote: > > > > On Mon, 2020-10-26 at 11:0

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-27 Thread David Hildenbrand
On 27.10.20 10:47, Mike Rapoport wrote: On Tue, Oct 27, 2020 at 09:46:35AM +0100, David Hildenbrand wrote: On 27.10.20 09:38, Mike Rapoport wrote: On Mon, Oct 26, 2020 at 06:05:30PM +, Edgecombe, Rick P wrote: On Mon, 2020-10-26 at 11:05 +0200, Mike Rapoport wrote: On Mon, Oct 26, 2020 at

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-27 Thread Mike Rapoport
On Tue, Oct 27, 2020 at 09:46:35AM +0100, David Hildenbrand wrote: > On 27.10.20 09:38, Mike Rapoport wrote: > > On Mon, Oct 26, 2020 at 06:05:30PM +, Edgecombe, Rick P wrote: > > > On Mon, 2020-10-26 at 11:05 +0200, Mike Rapoport wrote: > > > > On Mon, Oct 26, 2020 at 01:13:52AM +, Edgecom

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-27 Thread David Hildenbrand
On 27.10.20 09:38, Mike Rapoport wrote: On Mon, Oct 26, 2020 at 06:05:30PM +, Edgecombe, Rick P wrote: On Mon, 2020-10-26 at 11:05 +0200, Mike Rapoport wrote: On Mon, Oct 26, 2020 at 01:13:52AM +, Edgecombe, Rick P wrote: On Sun, 2020-10-25 at 12:15 +0200, Mike Rapoport wrote: Indeed,

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-27 Thread Mike Rapoport
On Mon, Oct 26, 2020 at 06:05:30PM +, Edgecombe, Rick P wrote: > On Mon, 2020-10-26 at 11:05 +0200, Mike Rapoport wrote: > > On Mon, Oct 26, 2020 at 01:13:52AM +, Edgecombe, Rick P wrote: > > > On Sun, 2020-10-25 at 12:15 +0200, Mike Rapoport wrote: > > > > Indeed, for architectures that de

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-26 Thread Edgecombe, Rick P
On Mon, 2020-10-26 at 11:05 +0200, Mike Rapoport wrote: > On Mon, Oct 26, 2020 at 01:13:52AM +, Edgecombe, Rick P wrote: > > On Sun, 2020-10-25 at 12:15 +0200, Mike Rapoport wrote: > > > Indeed, for architectures that define > > > CONFIG_ARCH_HAS_SET_DIRECT_MAP > > > it is > > > possible that _

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-26 Thread Mike Rapoport
On Mon, Oct 26, 2020 at 01:13:52AM +, Edgecombe, Rick P wrote: > On Sun, 2020-10-25 at 12:15 +0200, Mike Rapoport wrote: > > Indeed, for architectures that define CONFIG_ARCH_HAS_SET_DIRECT_MAP > > it is > > possible that __kernel_map_pages() would fail, but since this > > function is > > void,

Re: [PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-25 Thread Edgecombe, Rick P
On Sun, 2020-10-25 at 12:15 +0200, Mike Rapoport wrote: > Indeed, for architectures that define CONFIG_ARCH_HAS_SET_DIRECT_MAP > it is > possible that __kernel_map_pages() would fail, but since this > function is > void, the failure will go unnoticed. Could you elaborate on how this could happen?

[PATCH 0/4] arch, mm: improve robustness of direct map manipulation

2020-10-25 Thread Mike Rapoport
From: Mike Rapoport Hi, During recent discussion about KVM protected memory, David raised a concern about usage of __kernel_map_pages() outside of DEBUG_PAGEALLOC scope [1]. Indeed, for architectures that define CONFIG_ARCH_HAS_SET_DIRECT_MAP it is possible that __kernel_map_pages() would fail,