From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Fleming Subject: Re: [PATCH V4 0/3] Use mm_struct and switch_mm() instead of manually Date: Fri, 26 Jan 2018 21:16:43 +0000 Message-ID: <20180126211643.GB6520@codeblueprint.co.uk> References: <1516309264-23926-1-git-send-email-sai.praneeth.prakhya@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1516309264-23926-1-git-send-email-sai.praneeth.prakhya@intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Sai Praneeth Prakhya Cc: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, "Lee, Chun-Yi" , Borislav Petkov , Tony Luck , Andy Lutomirski , "Michael S. Tsirkin" , Ricardo Neri , Ard Biesheuvel , Ravi Shankar List-Id: linux-efi@vger.kernel.org On Thu, 18 Jan, at 01:01:04PM, Sai Praneeth Prakhya wrote: > From: Sai Praneeth > > Presently, in x86, to invoke any efi function like > efi_set_virtual_address_map() or any efi_runtime_service() the code path > typically involves read_cr3() (save previous pgd), write_cr3() > (write efi_pgd) and calling efi function. Likewise after returning from > efi function the code path typically involves read_cr3() (save efi_pgd), > write_cr3() (write previous pgd). We do this couple of times in efi > subsystem of Linux kernel, instead we can use helper function > efi_switch_mm() to do this. This improves readability and maintainability. > Also, instead of maintaining a separate struct "efi_scratch" to store/restore > efi_pgd, we can use mm_struct to do this. FWIW this series looks OK to me. Reviewed-by: Matt Fleming