From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Thu, 19 Oct 2017 15:11:28 +0000 (+0000)
Subject: x86/idt: Factor out enabling and disabling of ISTs
X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~729
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=f9fc2e584ddf3cf3b0b2a7b08dbc3ac3a70ddab3;p=xen.git

x86/idt: Factor out enabling and disabling of ISTs

All alteration of IST settings (other than the crash path) happen in an
identical triple.  Introduce helpers to keep the triple in sync, and reduce
the risk of opencoded mistakes.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Doug Goldstein <cardoe@cardoe.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
---

diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index 1ff121887c..4306e59650 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -771,9 +771,7 @@ void load_system_tables(void)
 	ltr(TSS_ENTRY << 3);
 	lldt(0);
 
-	set_ist(&idt_tables[cpu][TRAP_double_fault],  IST_DF);
-	set_ist(&idt_tables[cpu][TRAP_nmi],	      IST_NMI);
-	set_ist(&idt_tables[cpu][TRAP_machine_check], IST_MCE);
+	enable_each_ist(idt_tables[cpu]);
 
 	/*
 	 * Bottom-of-stack must be 16-byte aligned!
diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index 9d9ad777d1..6509b90c99 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -1038,9 +1038,7 @@ static void svm_ctxt_switch_from(struct vcpu *v)
     svm_vmload_pa(per_cpu(host_vmcb, cpu));
 
     /* Resume use of ISTs now that the host TR is reinstated. */
-    set_ist(&idt_tables[cpu][TRAP_double_fault],  IST_DF);
-    set_ist(&idt_tables[cpu][TRAP_nmi],           IST_NMI);
-    set_ist(&idt_tables[cpu][TRAP_machine_check], IST_MCE);
+    enable_each_ist(idt_tables[cpu]);
 }
 
 static void svm_ctxt_switch_to(struct vcpu *v)
@@ -1059,9 +1057,7 @@ static void svm_ctxt_switch_to(struct vcpu *v)
      * Cannot use ISTs for NMI/#MC/#DF while we are running with the guest TR.
      * But this doesn't matter: the IST is only req'd to handle SYSCALL/SYSRET.
      */
-    set_ist(&idt_tables[cpu][TRAP_double_fault],  IST_NONE);
-    set_ist(&idt_tables[cpu][TRAP_nmi],           IST_NONE);
-    set_ist(&idt_tables[cpu][TRAP_machine_check], IST_NONE);
+    disable_each_ist(idt_tables[cpu]);
 
     svm_restore_dr(v);
 
diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index 2cdd431b5f..fe637dae40 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -919,9 +919,7 @@ static int cpu_smpboot_alloc(unsigned int cpu)
     if ( idt_tables[cpu] == NULL )
         goto out;
     memcpy(idt_tables[cpu], idt_table, IDT_ENTRIES * sizeof(idt_entry_t));
-    set_ist(&idt_tables[cpu][TRAP_double_fault],  IST_NONE);
-    set_ist(&idt_tables[cpu][TRAP_nmi],           IST_NONE);
-    set_ist(&idt_tables[cpu][TRAP_machine_check], IST_NONE);
+    disable_each_ist(idt_tables[cpu]);
 
     rc = setup_cpu_root_pgt(cpu);
     if ( rc )
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index 513961cc87..181badde01 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -1889,9 +1889,7 @@ void __init init_idt_traps(void)
     set_intr_gate(TRAP_simd_error,&simd_coprocessor_error);
 
     /* Specify dedicated interrupt stacks for NMI, #DF, and #MC. */
-    set_ist(&idt_table[TRAP_double_fault],  IST_DF);
-    set_ist(&idt_table[TRAP_nmi],           IST_NMI);
-    set_ist(&idt_table[TRAP_machine_check], IST_MCE);
+    enable_each_ist(idt_table);
 
     /* CPU0 uses the master IDT. */
     idt_tables[0] = idt_table;
diff --git a/xen/include/asm-x86/processor.h b/xen/include/asm-x86/processor.h
index 80f8411355..9dd29bb04c 100644
--- a/xen/include/asm-x86/processor.h
+++ b/xen/include/asm-x86/processor.h
@@ -459,6 +459,20 @@ static always_inline void set_ist(idt_entry_t *idt, unsigned long ist)
     _write_gate_lower(idt, &new);
 }
 
+static inline void enable_each_ist(idt_entry_t *idt)
+{
+    set_ist(&idt[TRAP_double_fault],  IST_DF);
+    set_ist(&idt[TRAP_nmi],           IST_NMI);
+    set_ist(&idt[TRAP_machine_check], IST_MCE);
+}
+
+static inline void disable_each_ist(idt_entry_t *idt)
+{
+    set_ist(&idt[TRAP_double_fault],  IST_NONE);
+    set_ist(&idt[TRAP_nmi],           IST_NONE);
+    set_ist(&idt[TRAP_machine_check], IST_NONE);
+}
+
 #define IDT_ENTRIES 256
 extern idt_entry_t idt_table[];
 extern idt_entry_t *idt_tables[];