diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2020-04-10 14:54:00 +0300 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-04-11 17:39:30 +0300 |
| commit | d7e94dbdac1a40924626b0efc7ff530c8baf5e4a (patch) | |
| tree | 7e41876bdd753a6e9b0e6911cb03bcee99a1c320 /arch | |
| parent | 5b8b9d0c6d0e0f1993c6c56deaf9646942c49d94 (diff) | |
| download | linux-d7e94dbdac1a40924626b0efc7ff530c8baf5e4a.tar.xz | |
x86/split_lock: Provide handle_guest_split_lock()
Without at least minimal handling for split lock detection induced #AC,
VMX will just run into the same problem as the VMWare hypervisor, which
was reported by Kenneth.
It will inject the #AC blindly into the guest whether the guest is
prepared or not.
Provide a function for guest mode which acts depending on the host
SLD mode. If mode == sld_warn, treat it like user space, i.e. emit a
warning, disable SLD and mark the task accordingly. Otherwise force
SIGBUS.
[ bp: Add a !CPU_SUP_INTEL stub for handle_guest_split_lock(). ]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lkml.kernel.org/r/20200410115516.978037132@linutronix.de
Link: https://lkml.kernel.org/r/20200402123258.895628824@linutronix.de
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/cpu.h | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/intel.c | 33 |
2 files changed, 34 insertions, 5 deletions
diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h index ff6f3ca649b3..dd17c2da1af5 100644 --- a/arch/x86/include/asm/cpu.h +++ b/arch/x86/include/asm/cpu.h @@ -44,6 +44,7 @@ unsigned int x86_stepping(unsigned int sig); extern void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c); extern void switch_to_sld(unsigned long tifn); extern bool handle_user_split_lock(struct pt_regs *regs, long error_code); +extern bool handle_guest_split_lock(unsigned long ip); #else static inline void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c) {} static inline void switch_to_sld(unsigned long tifn) {} @@ -51,5 +52,10 @@ static inline bool handle_user_split_lock(struct pt_regs *regs, long error_code) { return false; } + +static inline bool handle_guest_split_lock(unsigned long ip) +{ + return false; +} #endif #endif /* _ASM_X86_CPU_H */ diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 9a26e972cdea..bf08d4508ecb 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -21,6 +21,7 @@ #include <asm/elf.h> #include <asm/cpu_device_id.h> #include <asm/cmdline.h> +#include <asm/traps.h> #ifdef CONFIG_X86_64 #include <linux/topology.h> @@ -1066,13 +1067,10 @@ static void split_lock_init(void) split_lock_verify_msr(sld_state != sld_off); } -bool handle_user_split_lock(struct pt_regs *regs, long error_code) +static void split_lock_warn(unsigned long ip) { - if ((regs->flags & X86_EFLAGS_AC) || sld_state == sld_fatal) - return false; - pr_warn_ratelimited("#AC: %s/%d took a split_lock trap at address: 0x%lx\n", - current->comm, current->pid, regs->ip); + current->comm, current->pid, ip); /* * Disable the split lock detection for this task so it can make @@ -1081,6 +1079,31 @@ bool handle_user_split_lock(struct pt_regs *regs, long error_code) */ sld_update_msr(false); set_tsk_thread_flag(current, TIF_SLD); +} + +bool handle_guest_split_lock(unsigned long ip) +{ + if (sld_state == sld_warn) { + split_lock_warn(ip); + return true; + } + + pr_warn_once("#AC: %s/%d %s split_lock trap at address: 0x%lx\n", + current->comm, current->pid, + sld_state == sld_fatal ? "fatal" : "bogus", ip); + + current->thread.error_code = 0; + current->thread.trap_nr = X86_TRAP_AC; + force_sig_fault(SIGBUS, BUS_ADRALN, NULL); + return false; +} +EXPORT_SYMBOL_GPL(handle_guest_split_lock); + +bool handle_user_split_lock(struct pt_regs *regs, long error_code) +{ + if ((regs->flags & X86_EFLAGS_AC) || sld_state == sld_fatal) + return false; + split_lock_warn(regs->ip); return true; } |