KVM: Rationalize exception bitmap usage

Everyone owns a piece of the exception bitmap, but they happily write to
the entire thing like there's no tomorrow.  Centralize handling in
update_exception_bitmap() and have everyone call that.

Signed-off-by: Avi Kivity <avi@qumranet.com>

diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 93c3abfc1e0a8ac446f200f69201f1fdb83fb50b..2190020e055b3c79bdbb29c0156c5f4bf2e216ad 100644 (file)
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -237,6 +237,20 @@ static void vmcs_set_bits(unsigned long field, u32 mask)
        vmcs_writel(field, vmcs_readl(field) | mask);
 }
 
+static void update_exception_bitmap(struct kvm_vcpu *vcpu)
+{
+       u32 eb;
+
+       eb = 1u << PF_VECTOR;
+       if (!vcpu->fpu_active)
+               eb |= 1u << NM_VECTOR;
+       if (vcpu->guest_debug.enabled)
+               eb |= 1u << 1;
+       if (vcpu->rmode.active)
+               eb = ~0;
+       vmcs_write32(EXCEPTION_BITMAP, eb);
+}
+
 static void reload_tss(void)
 {
 #ifndef CONFIG_X86_64
@@ -618,10 +632,8 @@ static void vcpu_put_rsp_rip(struct kvm_vcpu *vcpu)
 static int set_guest_debug(struct kvm_vcpu *vcpu, struct kvm_debug_guest *dbg)
 {
        unsigned long dr7 = 0x400;
-       u32 exception_bitmap;
        int old_singlestep;
 
-       exception_bitmap = vmcs_read32(EXCEPTION_BITMAP);
        old_singlestep = vcpu->guest_debug.singlestep;
 
        vcpu->guest_debug.enabled = dbg->enabled;
@@ -637,13 +649,9 @@ static int set_guest_debug(struct kvm_vcpu *vcpu, struct kvm_debug_guest *dbg)
                        dr7 |= 0 << (i*4+16); /* execution breakpoint */
                }
 
-               exception_bitmap |= (1u << 1);  /* Trap debug exceptions */
-
                vcpu->guest_debug.singlestep = dbg->singlestep;
-       } else {
-               exception_bitmap &= ~(1u << 1); /* Ignore debug exceptions */
+       } else
                vcpu->guest_debug.singlestep = 0;
-       }
 
        if (old_singlestep && !vcpu->guest_debug.singlestep) {
                unsigned long flags;
@@ -653,7 +661,7 @@ static int set_guest_debug(struct kvm_vcpu *vcpu, struct kvm_debug_guest *dbg)
                vmcs_writel(GUEST_RFLAGS, flags);
        }
 
-       vmcs_write32(EXCEPTION_BITMAP, exception_bitmap);
+       update_exception_bitmap(vcpu);
        vmcs_writel(GUEST_DR7, dr7);
 
        return 0;
@@ -767,14 +775,6 @@ static __exit void hardware_unsetup(void)
        free_kvm_area();
 }
 
-static void update_exception_bitmap(struct kvm_vcpu *vcpu)
-{
-       if (vcpu->rmode.active)
-               vmcs_write32(EXCEPTION_BITMAP, ~0);
-       else
-               vmcs_write32(EXCEPTION_BITMAP, 1 << PF_VECTOR);
-}
-
 static void fix_pmode_dataseg(int seg, struct kvm_save_segment *save)
 {
        struct kvm_vmx_segment_field *sf = &kvm_vmx_segment_fields[seg];
@@ -942,7 +942,7 @@ static void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 
        if (!(cr0 & CR0_TS_MASK)) {
                vcpu->fpu_active = 1;
-               vmcs_clear_bits(EXCEPTION_BITMAP, CR0_TS_MASK);
+               update_exception_bitmap(vcpu);
        }
 
        vmcs_writel(CR0_READ_SHADOW, cr0);
@@ -958,7 +958,7 @@ static void vmx_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
        if (!(vcpu->cr0 & CR0_TS_MASK)) {
                vcpu->fpu_active = 0;
                vmcs_set_bits(GUEST_CR0, CR0_TS_MASK);
-               vmcs_set_bits(EXCEPTION_BITMAP, 1 << NM_VECTOR);
+               update_exception_bitmap(vcpu);
        }
 }
 
@@ -1243,7 +1243,6 @@ static int vmx_vcpu_setup(struct kvm_vcpu *vcpu)
                               | CPU_BASED_USE_TSC_OFFSETING   /* 21.3 */
                        );
 
-       vmcs_write32(EXCEPTION_BITMAP, 1 << PF_VECTOR);
        vmcs_write32(PAGE_FAULT_ERROR_CODE_MASK, 0);
        vmcs_write32(PAGE_FAULT_ERROR_CODE_MATCH, 0);
        vmcs_write32(CR3_TARGET_COUNT, 0);           /* 22.2.1 */
@@ -1329,6 +1328,7 @@ static int vmx_vcpu_setup(struct kvm_vcpu *vcpu)
 #ifdef CONFIG_X86_64
        vmx_set_efer(vcpu, 0);
 #endif
+       update_exception_bitmap(vcpu);
 
        return 0;
 
@@ -1489,7 +1489,7 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 
        if (is_no_device(intr_info)) {
                vcpu->fpu_active = 1;
-               vmcs_clear_bits(EXCEPTION_BITMAP, 1 << NM_VECTOR);
+               update_exception_bitmap(vcpu);
                if (!(vcpu->cr0 & CR0_TS_MASK))
                        vmcs_clear_bits(GUEST_CR0, CR0_TS_MASK);
                return 1;
@@ -1684,7 +1684,7 @@ static int handle_cr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
        case 2: /* clts */
                vcpu_load_rsp_rip(vcpu);
                vcpu->fpu_active = 1;
-               vmcs_clear_bits(EXCEPTION_BITMAP, 1 << NM_VECTOR);
+               update_exception_bitmap(vcpu);
                vmcs_clear_bits(GUEST_CR0, CR0_TS_MASK);
                vcpu->cr0 &= ~CR0_TS_MASK;
                vmcs_writel(CR0_READ_SHADOW, vcpu->cr0);