linux_dsm_epyc7002/arch/x86/entry
Thomas Gleixner a377ac1cd9 x86/entry: Move user return notifier out of loop
Guests and user space share certain MSRs. KVM sets these MSRs to guest
values once and does not set them back to user space values on every VM
exit to spare the costly MSR operations.

User return notifiers ensure that these MSRs are set back to the correct
values before returning to user space in exit_to_usermode_loop().

There is no reason to evaluate the TIF flag indicating that user return
notifiers need to be invoked in the loop. The important point is that they
are invoked before returning to user space.

Move the invocation out of the loop into the section which does the last
preperatory steps before returning to user space. That section is not
preemptible and runs with interrupts disabled until the actual return.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200722220520.159112003@linutronix.de
2020-07-24 15:04:58 +02:00
..
syscalls vfs: add faccessat2 syscall 2020-05-14 16:44:25 +02:00
vdso Rebase locking/kcsan to locking/urgent 2020-06-11 20:02:46 +02:00
vsyscall y2038: syscall implementation cleanups 2019-12-01 14:00:59 -08:00
calling.h x86/entry: Remove the apic/BUILD interrupt leftovers 2020-06-11 15:15:16 +02:00
common.c x86/entry: Move user return notifier out of loop 2020-07-24 15:04:58 +02:00
entry_32.S x86/entry: Move SYSENTER's regs->sp and regs->flags fixups into C 2020-07-01 10:00:25 +02:00
entry_64_compat.S x86/entry/compat: Clear RAX high bits on Xen PV SYSENTER 2020-07-04 19:47:25 +02:00
entry_64.S x86/entry: Unbreak __irqentry_text_start/end magic 2020-06-11 15:15:29 +02:00
Makefile x86/entry: Actually disable stack protector 2020-07-19 13:07:10 +02:00
syscall_32.c x86/entry: Drop asmlinkage from syscalls 2020-03-21 16:03:25 +01:00
syscall_64.c x86/entry: Drop asmlinkage from syscalls 2020-03-21 16:03:25 +01:00
syscall_x32.c x86/entry: Drop asmlinkage from syscalls 2020-03-21 16:03:25 +01:00
thunk_32.S x86/entry: Rename ___preempt_schedule 2020-03-21 16:03:53 +01:00
thunk_64.S x86/entry: Remove the TRACE_IRQS cruft 2020-06-11 15:15:19 +02:00