Messages in this thread | | | Date | Thu, 16 Feb 2023 12:43:40 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH 1/2] x86/kexec: Preserve CR4.MCE during kexec |
| |
On Thu, Feb 16, 2023 at 01:49:39AM +0000, Edgecombe, Rick P wrote: > On Tue, 2023-02-14 at 02:48 +0300, Kirill A. Shutemov wrote: > > TDX guests are not allowed to clear CR4.MCE. Attempt to clear it > > leads > > to #VE. > > > > Preserve the flag during kexec. > > > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> > > I wonder whats going on with the pre-existing switching between eax and > rax in this code for the cr0 and cr4 manipulations. Do you know what > the reason is?
32-bit ORs and ANDs save one byte per instruction. And there's no 32-bit MOV to/from control registers in 64-bit mode.
> > Also, for a simple non-tdx kexec regression test: > Tested-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Thanks!
-- Kiryl Shutsemau / Kirill A. Shutemov
| |