[PATCH] KVM: IOAPIC: only access APIC registers one dword at a time
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From: Xiao Guangrong on 2 Jul 2010 00:50 The IOAPIC spec says: When accessing these registers, accesses must be done one dword at a time. For example, software should never access byte 2 from the Data register before accessing bytes 0 and 1. The hardware will not attempt to recover from a bad programming model in this case. So, this patch removes other width access Signed-off-by: Xiao Guangrong <xiaoguangrong(a)cn.fujitsu.com> --- virt/kvm/ioapic.c | 10 +++------- 1 files changed, 3 insertions(+), 7 deletions(-) diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c index 1149c60..f96816f 100644 --- a/virt/kvm/ioapic.c +++ b/virt/kvm/ioapic.c @@ -306,14 +306,10 @@ static int ioapic_mmio_read(struct kvm_io_device *this, gpa_t addr, int len, spin_unlock(&ioapic->lock); switch (len) { - case 8: - *(u64 *) val = result; - break; - case 1: - case 2: case 4: - memcpy(val, (char *)&result, len); + *(u32 *) val = result; break; + default: printk(KERN_WARNING "ioapic: wrong length %d\n", len); } @@ -332,7 +328,7 @@ static int ioapic_mmio_write(struct kvm_io_device *this, gpa_t addr, int len, (void*)addr, len, val); ASSERT(!(addr & 0xf)); /* check alignment */ - if (len == 4 || len == 8) + if (len == 4) data = *(u32 *) val; else { printk(KERN_WARNING "ioapic: Unsupported size %d\n", len); -- 1.6.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |