Re: [PATCH V3 05/14] KVM: MIPS: Use lddir/ldpte instructions to lookup gpa_mm.pgd

Aleksandar Markovic
2020-05-08T10:47:41Z

нед, 3. мај 2020. у 12:11 Huacai Chen <chenhc@lemote.com> је написао/ла:
>
> Loongson-3 can use lddir/ldpte instuctions to accelerate page table
> walking, so use them to lookup gpa_mm.pgd.
>
> Signed-off-by: Huacai Chen <chenhc@lemote.com>
> Co-developed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> ---
> arch/mips/kvm/entry.c | 19 ++++++++++++++++++-
> 1 file changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/arch/mips/kvm/entry.c b/arch/mips/kvm/entry.c
> index 16e1c93..fd71694 100644
> --- a/arch/mips/kvm/entry.c
> +++ b/arch/mips/kvm/entry.c
> @@ -56,6 +56,7 @@
> #define C0_BADVADDR 8, 0
> #define C0_BADINSTR 8, 1
> #define C0_BADINSTRP 8, 2
> +#define C0_PGD 9, 7
> #define C0_ENTRYHI 10, 0
> #define C0_GUESTCTL1 10, 4
> #define C0_STATUS 12, 0
> @@ -307,7 +308,10 @@ static void *kvm_mips_build_enter_guest(void *addr)
>
> #ifdef CONFIG_KVM_MIPS_VZ
> /* Save normal linux process pgd (VZ guarantees pgd_reg is set) */
> - UASM_i_MFC0(&p, K0, c0_kscratch(), pgd_reg);
> + if (cpu_has_ldpte)
> + UASM_i_MFC0(&p, K0, C0_PWBASE);
> + else
> + UASM_i_MFC0(&p, K0, c0_kscratch(), pgd_reg);
> UASM_i_SW(&p, K0, offsetof(struct kvm_vcpu_arch, host_pgd), K1);
>
> /*
> @@ -469,8 +473,10 @@ void *kvm_mips_build_tlb_refill_exception(void *addr, void *handler)
> u32 *p = addr;
> struct uasm_label labels[2];
> struct uasm_reloc relocs[2];
> +#ifndef CONFIG_CPU_LOONGSON64
> struct uasm_label *l = labels;
> struct uasm_reloc *r = relocs;
> +#endif
>
> memset(labels, 0, sizeof(labels));
> memset(relocs, 0, sizeof(relocs));
> @@ -490,6 +496,16 @@ void *kvm_mips_build_tlb_refill_exception(void *addr, void *handler)
> */
> preempt_disable();
>
> +#ifdef CONFIG_CPU_LOONGSON64
> + UASM_i_MFC0(&p, K1, C0_PGD);
> + uasm_i_lddir(&p, K0, K1, 3); /* global page dir */
> +#ifndef __PAGETABLE_PMD_FOLDED
> + uasm_i_lddir(&p, K1, K0, 1); /* middle page dir */
> +#endif
> + uasm_i_ldpte(&p, K1, 0); /* even */
> + uasm_i_ldpte(&p, K1, 1); /* odd */
> + uasm_i_tlbwr(&p);
> +#else
> /*
> * Now for the actual refill bit. A lot of this can be common with the
> * Linux TLB refill handler, however we don't need to handle so many
> @@ -512,6 +528,7 @@ void *kvm_mips_build_tlb_refill_exception(void *addr, void *handler)
> build_get_ptep(&p, K0, K1);
> build_update_entries(&p, K0, K1);
> build_tlb_write_entry(&p, &l, &r, tlb_random);
> +#endif
>
> preempt_enable();
>
> --
> 2.7.0
>
Reviewed-by: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>