[PATCH v2 08/22] mini-os: initialize trap handling for HVMlite

[Juergen Gross <jgross@suse.com>]

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 7b7869a..db1389a 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


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