diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2025-04-02 11:33:20 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2025-04-02 11:33:20 -0700 |
| commit | 6cb094583aef6533d0fd47ae7d134718da3399da (patch) | |
| tree | 4c96b5e4526287ee36875785c60a2840f1207064 /arch/x86/kernel | |
| parent | 92b71befc349587d58fdbbe6cdd68fb67f4933a8 (diff) | |
| parent | e8f45927ee5d99fa52f14205a2c7ac3820c64457 (diff) | |
Merge tag 'x86_tdx_for_6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 TDX updates from Dave Hansen:
"Avoid direct HLT instruction execution in TDX guests.
TDX guests aren't expected to use the HLT instruction directly. It
causes a virtualization exception (#VE). While the #VE _can_ be
handled, the current handling is slow and buggy and the easiest thing
is just to avoid HLT in the first place. Plus, the kernel already has
paravirt infrastructure that makes it relatively painless.
Make TDX guests require paravirt and add some TDX-specific paravirt
handlers which avoid HLT in the normal halt routines. Also add a
warning in case another HLT sneaks in.
There was a report that this leads to a "major performance
improvement" on specjbb2015, probably because of the extra #VE
overhead or missed wakeups from the buggy HLT handling"
* tag 'x86_tdx_for_6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/tdx: Emit warning if IRQs are enabled during HLT #VE handling
x86/tdx: Fix arch_safe_halt() execution for TDX VMs
x86/paravirt: Move halt paravirt calls under CONFIG_PARAVIRT
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/paravirt.c | 14 | ||||
| -rw-r--r-- | arch/x86/kernel/process.c | 2 |
2 files changed, 9 insertions, 7 deletions
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index 97925632c28e..1ccd05d8999f 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -75,6 +75,11 @@ void paravirt_set_sched_clock(u64 (*func)(void)) static_call_update(pv_sched_clock, func); } +static noinstr void pv_native_safe_halt(void) +{ + native_safe_halt(); +} + #ifdef CONFIG_PARAVIRT_XXL static noinstr void pv_native_write_cr2(unsigned long val) { @@ -100,11 +105,6 @@ static noinstr void pv_native_set_debugreg(int regno, unsigned long val) { native_set_debugreg(regno, val); } - -static noinstr void pv_native_safe_halt(void) -{ - native_safe_halt(); -} #endif struct pv_info pv_info = { @@ -161,9 +161,11 @@ struct paravirt_patch_template pv_ops = { .irq.save_fl = __PV_IS_CALLEE_SAVE(pv_native_save_fl), .irq.irq_disable = __PV_IS_CALLEE_SAVE(pv_native_irq_disable), .irq.irq_enable = __PV_IS_CALLEE_SAVE(pv_native_irq_enable), +#endif /* CONFIG_PARAVIRT_XXL */ + + /* Irq HLT ops. */ .irq.safe_halt = pv_native_safe_halt, .irq.halt = native_halt, -#endif /* CONFIG_PARAVIRT_XXL */ /* Mmu ops. */ .mmu.flush_tlb_user = native_flush_tlb_local, diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 91f6ff618852..962c3ce39323 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -939,7 +939,7 @@ void __init select_idle_routine(void) static_call_update(x86_idle, mwait_idle); } else if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) { pr_info("using TDX aware idle routine\n"); - static_call_update(x86_idle, tdx_safe_halt); + static_call_update(x86_idle, tdx_halt); } else { static_call_update(x86_idle, default_idle); } |