[Xen-devel] [PATCH 4/6] x86/hvm: Constify the read side of vlapic handling

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

This is in preparation to make hvm_x2apic_msr_read() take a const vcpu
pointer.  One modification is to alter vlapic_get_tmcct() to not use current.

This in turn needs an alteration to hvm_get_guest_time_fixed(), which is safe
because the only mutable action it makes is to take the domain plt lock.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Wei Liu <wei.liu2@xxxxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
---
 xen/arch/x86/hvm/vlapic.c     | 13 +++++++------
 xen/arch/x86/hvm/vpt.c        |  2 +-
 xen/include/asm-x86/hvm/hvm.h |  2 +-
 3 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/xen/arch/x86/hvm/vlapic.c b/xen/arch/x86/hvm/vlapic.c
index 7387f91..e715729 100644
--- a/xen/arch/x86/hvm/vlapic.c
+++ b/xen/arch/x86/hvm/vlapic.c
@@ -171,12 +171,12 @@ void vlapic_set_irq(struct vlapic *vlapic, uint8_t vec, 
uint8_t trig)
         vcpu_kick(target);
 }
 
-static int vlapic_find_highest_isr(struct vlapic *vlapic)
+static int vlapic_find_highest_isr(const struct vlapic *vlapic)
 {
     return vlapic_find_highest_vector(&vlapic->regs->data[APIC_ISR]);
 }
 
-static uint32_t vlapic_get_ppr(struct vlapic *vlapic)
+static uint32_t vlapic_get_ppr(const struct vlapic *vlapic)
 {
     uint32_t tpr, isrv, ppr;
     int isr;
@@ -550,9 +550,9 @@ void vlapic_ipi(
     }
 }
 
-static uint32_t vlapic_get_tmcct(struct vlapic *vlapic)
+static uint32_t vlapic_get_tmcct(const struct vlapic *vlapic)
 {
-    struct vcpu *v = current;
+    const struct vcpu *v = const_vlapic_vcpu(vlapic);
     uint32_t tmcct = 0, tmict = vlapic_get_reg(vlapic, APIC_TMICT);
     uint64_t counter_passed;
 
@@ -590,7 +590,8 @@ static void vlapic_set_tdcr(struct vlapic *vlapic, unsigned 
int val)
                 "timer_divisor: %d", vlapic->hw.timer_divisor);
 }
 
-static uint32_t vlapic_read_aligned(struct vlapic *vlapic, unsigned int offset)
+static uint32_t vlapic_read_aligned(const struct vlapic *vlapic,
+                                    unsigned int offset)
 {
     switch ( offset )
     {
@@ -680,7 +681,7 @@ int hvm_x2apic_msr_read(struct vcpu *v, unsigned int msr, 
uint64_t *msr_content)
             REGBLOCK(ISR) | REGBLOCK(TMR) | REGBLOCK(IRR)
 #undef REGBLOCK
         };
-    struct vlapic *vlapic = vcpu_vlapic(v);
+    const struct vlapic *vlapic = vcpu_vlapic(v);
     uint32_t high = 0, reg = msr - MSR_IA32_APICBASE_MSR, offset = reg << 4;
 
     if ( !vlapic_x2apic_mode(vlapic) ||
diff --git a/xen/arch/x86/hvm/vpt.c b/xen/arch/x86/hvm/vpt.c
index 181f4cb..862c715 100644
--- a/xen/arch/x86/hvm/vpt.c
+++ b/xen/arch/x86/hvm/vpt.c
@@ -35,7 +35,7 @@ void hvm_init_guest_time(struct domain *d)
     pl->last_guest_time = 0;
 }
 
-u64 hvm_get_guest_time_fixed(struct vcpu *v, u64 at_tsc)
+u64 hvm_get_guest_time_fixed(const struct vcpu *v, u64 at_tsc)
 {
     struct pl_time *pl = v->domain->arch.hvm_domain.pl_time;
     u64 now;
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index dd3dd5f..031af12 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -269,7 +269,7 @@ u64 hvm_get_tsc_scaling_ratio(u32 gtsc_khz);
 
 void hvm_init_guest_time(struct domain *d);
 void hvm_set_guest_time(struct vcpu *v, u64 guest_time);
-u64 hvm_get_guest_time_fixed(struct vcpu *v, u64 at_tsc);
+u64 hvm_get_guest_time_fixed(const struct vcpu *v, u64 at_tsc);
 #define hvm_get_guest_time(v) hvm_get_guest_time_fixed(v, 0)
 
 int vmsi_deliver(
-- 
2.1.4


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