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Subject[PATCH] kvm: LAPIC: write down valid APIC registers
Date
Replace a magic 64-bit mask with a list of valid registers, computing
the same mask in the end.

Suggested-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/lapic.c | 44 ++++++++++++++++++++++++++++++++------------
1 file changed, 32 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 2e4470f2685a..e4227ceab0c6 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1312,25 +1312,45 @@ static inline struct kvm_lapic *to_lapic(struct kvm_io_device *dev)
return container_of(dev, struct kvm_lapic, dev);
}

+#define APIC_REG_MASK(reg) (1ull << ((reg) >> 4))
+#define APIC_REGS_MASK(first, count) \
+ (APIC_REG_MASK(first) * ((1ull << (count)) - 1))
+
int kvm_lapic_reg_read(struct kvm_lapic *apic, u32 offset, int len,
void *data)
{
unsigned char alignment = offset & 0xf;
u32 result;
/* this bitmask has a bit cleared for each reserved register */
- u64 rmask = 0x43ff01ffffffe70cULL;
-
- if ((alignment + len) > 4) {
- apic_debug("KVM_APIC_READ: alignment error %x %d\n",
- offset, len);
- return 1;
- }
-
- /* ARBPRI is also reserved on x2APIC */
- if (apic_x2apic_mode(apic))
- rmask &= ~(1 << (APIC_ARBPRI >> 4));
+ u64 valid_reg_mask =
+ APIC_REG_MASK(APIC_ID) |
+ APIC_REG_MASK(APIC_LVR) |
+ APIC_REG_MASK(APIC_TASKPRI) |
+ APIC_REG_MASK(APIC_PROCPRI) |
+ APIC_REG_MASK(APIC_LDR) |
+ APIC_REG_MASK(APIC_DFR) |
+ APIC_REG_MASK(APIC_SPIV) |
+ APIC_REGS_MASK(APIC_ISR, APIC_ISR_NR) |
+ APIC_REGS_MASK(APIC_TMR, APIC_ISR_NR) |
+ APIC_REGS_MASK(APIC_IRR, APIC_ISR_NR) |
+ APIC_REG_MASK(APIC_ESR) |
+ APIC_REG_MASK(APIC_ICR) |
+ APIC_REG_MASK(APIC_ICR2) |
+ APIC_REG_MASK(APIC_LVTT) |
+ APIC_REG_MASK(APIC_LVTTHMR) |
+ APIC_REG_MASK(APIC_LVTPC) |
+ APIC_REG_MASK(APIC_LVT0) |
+ APIC_REG_MASK(APIC_LVT1) |
+ APIC_REG_MASK(APIC_LVTERR) |
+ APIC_REG_MASK(APIC_TMICT) |
+ APIC_REG_MASK(APIC_TMCCT) |
+ APIC_REG_MASK(APIC_TDCR);
+
+ /* ARBPRI is not valid on x2APIC */
+ if (!apic_x2apic_mode(apic))
+ valid_reg_mask |= APIC_REG_MASK(APIC_ARBPRI);

- if (offset > 0x3f0 || !(rmask & (1ULL << (offset >> 4)))) {
+ if (offset > 0x3f0 || !(valid_reg_mask & APIC_REG_MASK(offset))) {
apic_debug("KVM_APIC_READ: read reserved register %x\n",
offset);
return 1;
--
1.8.3.1
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