On Mon, Nov 21, 2022 at 08:39:15AM +0800, Chen Lifu wrote:
> The values of CSR_HEDELEG and CSR_HIDELEG registers are constants,
> so change them from variables to macros.
>
> Signed-off-by: Chen Lifu <chenlifu@xxxxxxxxxx>
> ---
> arch/riscv/kvm/main.c | 31 +++++++++++++------------------
> 1 file changed, 13 insertions(+), 18 deletions(-)
>
> diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c
> index df2d8716851f..70196b03b6f9 100644
> --- a/arch/riscv/kvm/main.c
> +++ b/arch/riscv/kvm/main.c
> @@ -12,10 +12,21 @@
> #include <linux/kvm_host.h>
> #include <asm/csr.h>
> #include <asm/hwcap.h>
> #include <asm/sbi.h>
>
> +#define EXC_HEDELEG ((1UL << EXC_INST_MISALIGNED) | \
> + (1UL << EXC_BREAKPOINT) | \
> + (1UL << EXC_SYSCALL) | \
> + (1UL << EXC_INST_PAGE_FAULT) | \
> + (1UL << EXC_LOAD_PAGE_FAULT) | \
> + (1UL << EXC_STORE_PAGE_FAULT))
> +
> +#define IRQ_HIDELEG ((1UL << IRQ_VS_SOFT) | \
> + (1UL << IRQ_VS_TIMER) | \
> + (1UL << IRQ_VS_EXT))
> +
> long kvm_arch_dev_ioctl(struct file *filp,
> unsigned int ioctl, unsigned long arg)
> {
> return -EINVAL;
> }
> @@ -30,29 +41,13 @@ int kvm_arch_hardware_setup(void *opaque)
> return 0;
> }
>
> int kvm_arch_hardware_enable(void)
> {
> - unsigned long hideleg, hedeleg;
> -
> - hedeleg = 0;
> - hedeleg |= (1UL << EXC_INST_MISALIGNED);
> - hedeleg |= (1UL << EXC_BREAKPOINT);
> - hedeleg |= (1UL << EXC_SYSCALL);
> - hedeleg |= (1UL << EXC_INST_PAGE_FAULT);
> - hedeleg |= (1UL << EXC_LOAD_PAGE_FAULT);
> - hedeleg |= (1UL << EXC_STORE_PAGE_FAULT);
> - csr_write(CSR_HEDELEG, hedeleg);
> -
> - hideleg = 0;
> - hideleg |= (1UL << IRQ_VS_SOFT);
> - hideleg |= (1UL << IRQ_VS_TIMER);
> - hideleg |= (1UL << IRQ_VS_EXT);
> - csr_write(CSR_HIDELEG, hideleg);
> -
> + csr_write(CSR_HEDELEG, EXC_HEDELEG);
> + csr_write(CSR_HIDELEG, IRQ_HIDELEG);
> csr_write(CSR_HCOUNTEREN, -1UL);
> -
> csr_write(CSR_HVIP, 0);
>
> return 0;
> }
>
> --
> 2.37.1
>
I don't think this optimizes anything. I'm pretty sure the compiler will
load the input to csr_write() in the most efficient way it can, regardless
of using a constant or building the input out of constants. This could
maybe be considered a code cleanup, but, in this case, it's really in the
eye of the beholder.
Thanks,
drew
