Re: [PATCH V3 07/14] KVM: MIPS: Use root tlb to control guest's CCA for Loongson-3

Aleksandar Markovic
2020-05-08T10:54:27Z

нед, 3. мај 2020. у 12:12 Huacai Chen <chenhc@lemote.com> је написао/ла:
>
> KVM guest has two levels of address translation: guest tlb translates
> GVA to GPA, and root tlb translates GPA to HPA. By default guest's CCA
> is controlled by guest tlb, but Loongson-3 maintains all cache coherency
> by hardware (including multi-core coherency and I/O DMA coherency) so it
> prefers all guest mappings be cacheable mappings. Thus, we use root tlb
> to control guest's CCA for Loongson-3.
>
> Signed-off-by: Huacai Chen <chenhc@lemote.com>
> Co-developed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> ---
> arch/mips/kvm/vz.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/arch/mips/kvm/vz.c b/arch/mips/kvm/vz.c
> index 422cd06..f9fbbc16 100644
> --- a/arch/mips/kvm/vz.c
> +++ b/arch/mips/kvm/vz.c
> @@ -2871,6 +2871,12 @@ static int kvm_vz_hardware_enable(void)
> if (cpu_has_guestctl2)
> clear_c0_guestctl2(0x3f << 10);
>
> +#ifdef CONFIG_CPU_LOONGSON64
> + /* Control guest CCA attribute */
> + if (cpu_has_csr())
> + csr_writel(csr_readl(0xffffffec) | 0x1, 0xffffffec);
> +#endif
> +
> return 0;
> }
>
> --
> 2.7.0
>

Reviewed-by: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>