Re: [PATCH 08/22] mini-os: initialize trap handling for HVMlite

[Samuel Thibault <samuel.thibault@ens-lyon.org>]

Juergen Gross, on Tue 23 Aug 2016 17:15:54 +0200, wrote:
> Trap handling for HVMlite domains requires an initialized IDT.
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>

Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

> ---
>  arch/x86/setup.c  | 15 ----------
>  arch/x86/traps.c  | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  arch/x86/x86_64.S |  4 +++
>  include/x86/os.h  |  1 +
>  4 files changed, 93 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/x86/setup.c b/arch/x86/setup.c
> index edc4ca4..efecefb 100644
> --- a/arch/x86/setup.c
> +++ b/arch/x86/setup.c
> @@ -52,10 +52,6 @@ char stack[2*STACK_SIZE];
>  
>  extern char shared_info[PAGE_SIZE];
>  
> -/* Assembler interface fns in entry.S. */
> -void hypervisor_callback(void);
> -void failsafe_callback(void);
> -
>  #if defined(__x86_64__)
>  #define __pte(x) ((pte_t) { (x) } )
>  #else
> @@ -162,17 +158,6 @@ arch_init(void *par)
>  	/* Grab the shared_info pointer and put it in a safe place. */
>  	HYPERVISOR_shared_info = map_shared_info(start_info.shared_info);
>  
> -	    /* Set up event and failsafe callback addresses. */
> -#ifdef __i386__
> -	HYPERVISOR_set_callbacks(
> -		__KERNEL_CS, (unsigned long)hypervisor_callback,
> -		__KERNEL_CS, (unsigned long)failsafe_callback);
> -#else
> -	HYPERVISOR_set_callbacks(
> -		(unsigned long)hypervisor_callback,
> -		(unsigned long)failsafe_callback, 0);
> -#endif
> -
>  	start_kernel();
>  }
>  
> diff --git a/arch/x86/traps.c b/arch/x86/traps.c
> index 307a14c..3b1fffb 100644
> --- a/arch/x86/traps.c
> +++ b/arch/x86/traps.c
> @@ -1,10 +1,12 @@
>  
>  #include <mini-os/os.h>
>  #include <mini-os/traps.h>
> +#include <mini-os/desc.h>
>  #include <mini-os/hypervisor.h>
>  #include <mini-os/mm.h>
>  #include <mini-os/lib.h>
>  #include <mini-os/sched.h>
> +#include <xen/hvm/params.h>
>  
>  /*
>   * These are assembler stubs in entry.S.
> @@ -293,6 +295,11 @@ void do_spurious_interrupt_bug(struct pt_regs * regs)
>  {
>  }
>  
> +/* Assembler interface fns in entry.S. */
> +void hypervisor_callback(void);
> +void failsafe_callback(void);
> +
> +#ifdef CONFIG_PARAVIRT
>  /*
>   * Submit a virtual IDT to teh hypervisor. This consists of tuples
>   * (interrupt vector, privilege ring, CS:EIP of handler).
> @@ -325,9 +332,90 @@ static trap_info_t trap_table[] = {
>  void trap_init(void)
>  {
>      HYPERVISOR_set_trap_table(trap_table);    
> +
> +#ifdef __i386__
> +    HYPERVISOR_set_callbacks(
> +        __KERNEL_CS, (unsigned long)hypervisor_callback,
> +        __KERNEL_CS, (unsigned long)failsafe_callback);
> +#else
> +    HYPERVISOR_set_callbacks(
> +        (unsigned long)hypervisor_callback,
> +        (unsigned long)failsafe_callback, 0);
> +#endif
>  }
>  
>  void trap_fini(void)
>  {
>      HYPERVISOR_set_trap_table(NULL);
>  }
> +#else
> +
> +#define INTR_STACK_SIZE PAGE_SIZE
> +static uint8_t intr_stack[INTR_STACK_SIZE] __attribute__((aligned(16)));
> +
> +hw_tss tss __attribute__((aligned(16))) =
> +{
> +#if defined(__i386__)
> +    .esp0 = (unsigned long)&intr_stack[INTR_STACK_SIZE],
> +    .ss0  = __KERN_DS,
> +#elif defined(__x86_64__)
> +    .rsp0 = (unsigned long)&intr_stack[INTR_STACK_SIZE],
> +#endif
> +    .iopb = X86_TSS_INVALID_IO_BITMAP,
> +};
> +
> +static void setup_gate(unsigned int entry, void *addr, unsigned int dpl)
> +{
> +    idt[entry].offset0 = (unsigned long)addr & 0xffff;
> +    idt[entry].selector = __KERN_CS;
> +    idt[entry]._r0 = 0;
> +    idt[entry].type = 14;
> +    idt[entry].s = 0;
> +    idt[entry].dpl = dpl;
> +    idt[entry].p = 1;
> +    idt[entry].offset1 = ((unsigned long)addr >> 16) & 0xffff;
> +#if defined(__x86_64__)
> +    idt[entry].ist = 0;
> +    idt[entry].offset2 = ((unsigned long)addr >> 32) & 0xffffffffu;
> +    idt[entry]._r1 = 0;
> +#endif
> +}
> +
> +void trap_init(void)
> +{
> +    setup_gate(TRAP_divide_error, &divide_error, 0);
> +    setup_gate(TRAP_debug, &debug, 0);
> +    setup_gate(TRAP_int3, &int3, 3);
> +    setup_gate(TRAP_overflow, &overflow, 3);
> +    setup_gate(TRAP_bounds, &bounds, 0);
> +    setup_gate(TRAP_invalid_op, &invalid_op, 0);
> +    setup_gate(TRAP_no_device, &device_not_available, 0);
> +    setup_gate(TRAP_copro_seg, &coprocessor_segment_overrun, 0);
> +    setup_gate(TRAP_invalid_tss, &invalid_TSS, 0);
> +    setup_gate(TRAP_no_segment, &segment_not_present, 0);
> +    setup_gate(TRAP_stack_error, &stack_segment, 0);
> +    setup_gate(TRAP_gp_fault, &general_protection, 0);
> +    setup_gate(TRAP_page_fault, &page_fault, 0);
> +    setup_gate(TRAP_spurious_int, &spurious_interrupt_bug, 0);
> +    setup_gate(TRAP_copro_error, &coprocessor_error, 0);
> +    setup_gate(TRAP_alignment_check, &alignment_check, 0);
> +    setup_gate(TRAP_simd_error, &simd_coprocessor_error, 0);
> +    setup_gate(TRAP_xen_callback, hypervisor_callback, 0);
> +
> +    asm volatile ("lidt idt_ptr");
> +
> +    gdt[GDTE_TSS] = (typeof(*gdt))INIT_GDTE((unsigned long)&tss, 0x67, 0x89);
> +    asm volatile ("ltr %w0" :: "rm" (GDTE_TSS * 8));
> +
> +    if ( hvm_set_parameter(HVM_PARAM_CALLBACK_IRQ,
> +                           (2ULL << 56) | TRAP_xen_callback) )
> +    {
> +        xprintk("Request for Xen HVM callback vector failed\n");
> +        do_exit();
> +    }
> +}
> +
> +void trap_fini(void)
> +{
> +}
> +#endif
> diff --git a/arch/x86/x86_64.S b/arch/x86/x86_64.S
> index 373f400..e725c63 100644
> --- a/arch/x86/x86_64.S
> +++ b/arch/x86/x86_64.S
> @@ -130,18 +130,22 @@ KERNEL_CS_MASK = 0xfc
>  .endm
>  
>  .macro HYPERVISOR_IRET flag
> +#ifdef CONFIG_PARAVIRT
>  	testl $NMI_MASK,2*8(%rsp)
>  	jnz   2f
> +#endif
>  
>  	/* Direct iret to kernel space. Correct CS and SS. */
>  	orb   $3,1*8(%rsp)
>  	orb   $3,4*8(%rsp)
>  	iretq
>  
> +#ifdef CONFIG_PARAVIRT
>  2:	/* Slow iret via hypervisor. */
>  	andl  $~NMI_MASK, 16(%rsp)
>  	pushq $\flag
>  	jmp  hypercall_page + (__HYPERVISOR_iret * 32)
> +#endif
>  .endm
>  
>  
> diff --git a/include/x86/os.h b/include/x86/os.h
> index 610d8e0..6826b9f 100644
> --- a/include/x86/os.h
> +++ b/include/x86/os.h
> @@ -56,6 +56,7 @@
>  #define TRAP_machine_check    18
>  #define TRAP_simd_error       19
>  #define TRAP_deferred_nmi     31
> +#define TRAP_xen_callback     32
>  
>  /* Everything below this point is not included by assembler (.S) files. */
>  #ifndef __ASSEMBLY__
> -- 
> 2.6.6
> 

-- 
Samuel
 RM> Mauvais OS, changer d'OS (c)(r)(tm)
 J'ai windows 98 et comment faire pour changer l'os de windows 98?
 Dans ajout et suppression du programme et il ne parle pas d'os.
 -+- DN in : GNU -+- L'O.S. est las, hélas, c'est là qu'est l'os -+-

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