xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

x86/entry: Optimize local_db_save() for virt

Browse Source 
Because DRn access is 'difficult' with virt; but the DR7 read is cheaper
than a cacheline miss on native, add a virt specific fast path to
local_db_save(), such that when breakpoints are not in use to avoid
touching DRn entirely.

Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200529213321.187833200@infradead.org
This commit is contained in:
Peter Zijlstra
2020-05-29 23:27:36 +02:00
committed by Thomas Gleixner
parent cd840e424f
commit 84b6a34915
3 changed files with 27 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/kvm/vmx/nested.c
View File

@@ -3087,9 +3087,9 @@ static int nested_vmx_check_vmentry_hw(struct kvm_vcpu *vcpu)
/*
* VMExit clears RFLAGS.IF and DR7, even on a consistency check.
*/
local_irq_enable();
if (hw_breakpoint_active())
set_debugreg(__this_cpu_read(cpu_dr7), 7);
local_irq_enable();
preempt_enable();
/*