Re: [PATCH 4.14] x86/pae: use 64 bit atomic xchg function in native_ptep_get_and_clear

2018-09-13 Thread Greg KH
On Thu, Sep 13, 2018 at 11:56:11AM -0400, Jason Andryuk wrote: > From: Juergen Gross > > commit b2d7a075a1ccef2fb321d595802190c8e9b39004 upstream > > Using only 32-bit writes for the pte will result in an intermediate > L1TF vulnerable PTE. When running as a Xen PV guest this will at once > swit

[PATCH 4.14] x86/pae: use 64 bit atomic xchg function in native_ptep_get_and_clear

2018-09-13 Thread Jason Andryuk
From: Juergen Gross commit b2d7a075a1ccef2fb321d595802190c8e9b39004 upstream Using only 32-bit writes for the pte will result in an intermediate L1TF vulnerable PTE. When running as a Xen PV guest this will at once switch the guest to shadow mode resulting in a loss of performance. Use arch_ato