2015-06-09 00:36:37

by David Matlack

Subject: Re: [PATCH 09/15] KVM: MTRR: introduce var_mtrr_range

On Sat, May 30, 2015 at 3:59 AM, Xiao Guangrong
<[email protected]> wrote:
> It gets the range for the specified variable MTRR
>
> Signed-off-by: Xiao Guangrong <[email protected]>
> ---
> arch/x86/kvm/mtrr.c | 19 +++++++++++++------
> 1 file changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kvm/mtrr.c b/arch/x86/kvm/mtrr.c
> index 888441e..aeb9767 100644
> --- a/arch/x86/kvm/mtrr.c
> +++ b/arch/x86/kvm/mtrr.c
> @@ -217,10 +217,21 @@ static int fixed_msr_to_range_index(u32 msr)
> return 0;
> }
>
> +static void var_mtrr_range(struct kvm_mtrr_range *range, u64 *start, u64 *end)
> +{
> + u64 mask;
> +
> + *start = range->base & PAGE_MASK;
> +
> + mask = range->mask & PAGE_MASK;
> + mask |= ~0ULL << boot_cpu_data.x86_phys_bits;
> + *end = ((*start & mask) | ~mask) + 1;
> +}
> +
> static void update_mtrr(struct kvm_vcpu *vcpu, u32 msr)
> {
> struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
> - gfn_t start, end, mask;
> + gfn_t start, end;
> int index;
>
> if (msr == MSR_IA32_CR_PAT || !tdp_enabled ||
> @@ -244,11 +255,7 @@ static void update_mtrr(struct kvm_vcpu *vcpu, u32 msr)
> default:
> /* variable range MTRRs. */
> index = (msr - 0x200) / 2;
> - start = mtrr_state->var_ranges[index].base & PAGE_MASK;
> - mask = mtrr_state->var_ranges[index].mask & PAGE_MASK;
> - mask |= ~0ULL << cpuid_maxphyaddr(vcpu);

Why did you drop this in favor of boot_cpu_data.x86_phys_bits?

> -
> - end = ((start & mask) | ~mask) + 1;
> + var_mtrr_range(&mtrr_state->var_ranges[index], &start, &end);
> }
>
> do_zap:
> --
> 2.1.0
>
> --
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2015-06-09 02:43:06

by Xiao Guangrong

Subject: Re: [PATCH 09/15] KVM: MTRR: introduce var_mtrr_range

Thanks for your review, David!


On 06/09/2015 08:36 AM, David Matlack wrote:

>> static void update_mtrr(struct kvm_vcpu *vcpu, u32 msr)
>> {
>> struct kvm_mtrr *mtrr_state = &vcpu->arch.mtrr_state;
>> - gfn_t start, end, mask;
>> + gfn_t start, end;
>> int index;
>>
>> if (msr == MSR_IA32_CR_PAT || !tdp_enabled ||
>> @@ -244,11 +255,7 @@ static void update_mtrr(struct kvm_vcpu *vcpu, u32 msr)
>> default:
>> /* variable range MTRRs. */
>> index = (msr - 0x200) / 2;
>> - start = mtrr_state->var_ranges[index].base & PAGE_MASK;
>> - mask = mtrr_state->var_ranges[index].mask & PAGE_MASK;
>> - mask |= ~0ULL << cpuid_maxphyaddr(vcpu);
>
> Why did you drop this in favor of boot_cpu_data.x86_phys_bits?
>

It can make the code more generic, @vcpu is not needed anymore.