[PATCH 14/58] KVM: Rationalize exception bitmap usage

Avi Kivity
2007-06-17T09:43:55Z

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-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
---
drivers/kvm/vmx.c | 42 +++++++++++++++++++++---------------------
1 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 93c3abf..2190020 100644
--- 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);