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a0d14b8909
Despite the current efforts to read CR2 before tracing happens there still
exist a number of possible holes:
idtentry page_fault do_page_fault has_error_code=1
call error_entry
TRACE_IRQS_OFF
call trace_hardirqs_off*
#PF // modifies CR2
CALL_enter_from_user_mode
__context_tracking_exit()
trace_user_exit(0)
#PF // modifies CR2
call do_page_fault
address = read_cr2(); /* whoopsie */
And similar for i386.
Fix it by pulling the CR2 read into the entry code, before any of that
stuff gets a chance to run and ruin things.
Reported-by: He Zhe <zhe.he@windriver.com>
Reported-by: Eiichi Tsukata <devel@etsukata.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Cc: bp@alien8.de
Cc: rostedt@goodmis.org
Cc: torvalds@linux-foundation.org
Cc: hpa@zytor.com
Cc: dave.hansen@linux.intel.com
Cc: jgross@suse.com
Cc: joel@joelfernandes.org
Link: https://lkml.kernel.org/r/20190711114336.116812491@infradead.org
Debugged-by: Steven Rostedt <rostedt@goodmis.org>
136 lines
3.2 KiB
C
136 lines
3.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_KVM_PARA_H
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#define _ASM_X86_KVM_PARA_H
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#include <asm/processor.h>
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#include <asm/alternative.h>
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#include <uapi/asm/kvm_para.h>
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extern void kvmclock_init(void);
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#ifdef CONFIG_KVM_GUEST
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bool kvm_check_and_clear_guest_paused(void);
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#else
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static inline bool kvm_check_and_clear_guest_paused(void)
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{
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return false;
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}
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#endif /* CONFIG_KVM_GUEST */
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#define KVM_HYPERCALL \
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ALTERNATIVE(".byte 0x0f,0x01,0xc1", ".byte 0x0f,0x01,0xd9", X86_FEATURE_VMMCALL)
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/* For KVM hypercalls, a three-byte sequence of either the vmcall or the vmmcall
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* instruction. The hypervisor may replace it with something else but only the
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* instructions are guaranteed to be supported.
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*
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* Up to four arguments may be passed in rbx, rcx, rdx, and rsi respectively.
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* The hypercall number should be placed in rax and the return value will be
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* placed in rax. No other registers will be clobbered unless explicitly
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* noted by the particular hypercall.
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*/
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static inline long kvm_hypercall0(unsigned int nr)
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{
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long ret;
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asm volatile(KVM_HYPERCALL
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: "=a"(ret)
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: "a"(nr)
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: "memory");
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return ret;
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}
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static inline long kvm_hypercall1(unsigned int nr, unsigned long p1)
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{
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long ret;
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asm volatile(KVM_HYPERCALL
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: "=a"(ret)
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: "a"(nr), "b"(p1)
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: "memory");
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return ret;
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}
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static inline long kvm_hypercall2(unsigned int nr, unsigned long p1,
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unsigned long p2)
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{
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long ret;
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asm volatile(KVM_HYPERCALL
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: "=a"(ret)
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: "a"(nr), "b"(p1), "c"(p2)
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: "memory");
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return ret;
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}
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static inline long kvm_hypercall3(unsigned int nr, unsigned long p1,
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unsigned long p2, unsigned long p3)
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{
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long ret;
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asm volatile(KVM_HYPERCALL
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: "=a"(ret)
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: "a"(nr), "b"(p1), "c"(p2), "d"(p3)
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: "memory");
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return ret;
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}
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static inline long kvm_hypercall4(unsigned int nr, unsigned long p1,
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unsigned long p2, unsigned long p3,
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unsigned long p4)
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{
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long ret;
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asm volatile(KVM_HYPERCALL
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: "=a"(ret)
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: "a"(nr), "b"(p1), "c"(p2), "d"(p3), "S"(p4)
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: "memory");
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return ret;
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}
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#ifdef CONFIG_KVM_GUEST
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bool kvm_para_available(void);
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unsigned int kvm_arch_para_features(void);
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unsigned int kvm_arch_para_hints(void);
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void kvm_async_pf_task_wait(u32 token, int interrupt_kernel);
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void kvm_async_pf_task_wake(u32 token);
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u32 kvm_read_and_reset_pf_reason(void);
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extern void kvm_disable_steal_time(void);
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void do_async_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address);
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#ifdef CONFIG_PARAVIRT_SPINLOCKS
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void __init kvm_spinlock_init(void);
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#else /* !CONFIG_PARAVIRT_SPINLOCKS */
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static inline void kvm_spinlock_init(void)
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{
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}
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#endif /* CONFIG_PARAVIRT_SPINLOCKS */
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#else /* CONFIG_KVM_GUEST */
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#define kvm_async_pf_task_wait(T, I) do {} while(0)
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#define kvm_async_pf_task_wake(T) do {} while(0)
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static inline bool kvm_para_available(void)
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{
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return false;
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}
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static inline unsigned int kvm_arch_para_features(void)
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{
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return 0;
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}
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static inline unsigned int kvm_arch_para_hints(void)
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{
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return 0;
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}
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static inline u32 kvm_read_and_reset_pf_reason(void)
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{
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return 0;
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}
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static inline void kvm_disable_steal_time(void)
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{
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return;
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}
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#endif
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#endif /* _ASM_X86_KVM_PARA_H */
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