He, Qing wrote:
> This patch enables IO bitmaps control on vmx and unmask the 0x80 port to
> avoid VMEXITs caused by accessing port 0x80. 0x80 is used as delays (see
> include/asm/io.h), and handling VMEXITs on its access is unnecessary but
> slows things down. This patch improves kernel build test at around
> 3%~5%.
>
It's quite surprising to see such a large speedup!
> +
> #ifdef CONFIG_X86_64
> #define HOST_IS_64 1
> #else
> @@ -1127,8 +1129,8 @@ static int vmx_vcpu_setup(struct kvm_vcpu *vcpu)
> vmcs_write32(GUEST_PENDING_DBG_EXCEPTIONS, 0);
>
> /* I/O */
> - vmcs_write64(IO_BITMAP_A, 0);
> - vmcs_write64(IO_BITMAP_B, 0);
> + vmcs_write64(IO_BITMAP_A, (unsigned long) __pa(vmx_io_bitmap));
> + vmcs_write64(IO_BITMAP_B, (unsigned long) __pa(vmx_io_bitmap +
> PAGE_SIZE));
>
Unnecessary casts.
> + r = kvm_init_arch(&vmx_arch_ops, THIS_MODULE);
> + if (r) {
> + goto out1;
> + }
>
No braces around single statements in kernel code, please.
> +
> + return 0;
> +
> +out1:
> + free_pages((unsigned long) vmx_io_bitmap, 1);
> +out:
> + return r;
> }
>
> static void __exit vmx_exit(void)
> {
> + if (vmx_io_bitmap)
> + free_pages((unsigned long) vmx_io_bitmap, 1);
>
The if is unnecessary, since we can't get here with a NULL vmx_io_bitmap
(also free_pages() checks for NULL).
--
error compiling committee.c: too many arguments to function
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