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Message-ID: <26c87b3e-7a89-6cfa-1410-25486b114f32@redhat.com>
Date: Wed, 31 Mar 2021 09:41:34 +0200
From: Paolo Bonzini <pbonzini@...hat.com>
To: Sean Christopherson <seanjc@...gle.com>,
Marc Zyngier <maz@...nel.org>,
Huacai Chen <chenhuacai@...nel.org>,
Aleksandar Markovic <aleksandar.qemu.devel@...il.com>,
Paul Mackerras <paulus@...abs.org>
Cc: James Morse <james.morse@....com>,
Julien Thierry <julien.thierry.kdev@...il.com>,
Suzuki K Poulose <suzuki.poulose@....com>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Wanpeng Li <wanpengli@...cent.com>,
Jim Mattson <jmattson@...gle.com>,
Joerg Roedel <joro@...tes.org>,
linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
linux-mips@...r.kernel.org, kvm@...r.kernel.org,
kvm-ppc@...r.kernel.org, linux-kernel@...r.kernel.org,
Ben Gardon <bgardon@...gle.com>
Subject: Re: [PATCH 12/18] KVM: MIPS/MMU: Convert to the gfn-based MMU
notifier callbacks
On 26/03/21 03:19, Sean Christopherson wrote:
> Move MIPS to the gfn-based MMU notifier APIs, which do the hva->gfn
> lookup in common code, and whose code is nearly identical to MIPS'
> lookup.
>
> No meaningful functional change intended, though the exact order of
> operations is slightly different since the memslot lookups occur before
> calling into arch code.
>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
I'll post a couple patches to enable more coalescing of the flushes, but
this particular patch is okay.
Paolo
> ---
> arch/mips/include/asm/kvm_host.h | 1 +
> arch/mips/kvm/mmu.c | 97 ++++++--------------------------
> 2 files changed, 17 insertions(+), 81 deletions(-)
>
> diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
> index feaa77036b67..374a3c8806e8 100644
> --- a/arch/mips/include/asm/kvm_host.h
> +++ b/arch/mips/include/asm/kvm_host.h
> @@ -967,6 +967,7 @@ enum kvm_mips_fault_result kvm_trap_emul_gva_fault(struct kvm_vcpu *vcpu,
> bool write);
>
> #define KVM_ARCH_WANT_MMU_NOTIFIER
> +#define KVM_ARCH_WANT_NEW_MMU_NOTIFIER_APIS
>
> /* Emulation */
> int kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu, u32 *out);
> diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
> index 3dabeda82458..3dc885df2e32 100644
> --- a/arch/mips/kvm/mmu.c
> +++ b/arch/mips/kvm/mmu.c
> @@ -439,85 +439,36 @@ static int kvm_mips_mkold_gpa_pt(struct kvm *kvm, gfn_t start_gfn,
> end_gfn << PAGE_SHIFT);
> }
>
> -static int handle_hva_to_gpa(struct kvm *kvm,
> - unsigned long start,
> - unsigned long end,
> - int (*handler)(struct kvm *kvm, gfn_t gfn,
> - gpa_t gfn_end,
> - struct kvm_memory_slot *memslot,
> - void *data),
> - void *data)
> +bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
> {
> - struct kvm_memslots *slots;
> - struct kvm_memory_slot *memslot;
> - int ret = 0;
> -
> - slots = kvm_memslots(kvm);
> -
> - /* we only care about the pages that the guest sees */
> - kvm_for_each_memslot(memslot, slots) {
> - unsigned long hva_start, hva_end;
> - gfn_t gfn, gfn_end;
> -
> - hva_start = max(start, memslot->userspace_addr);
> - hva_end = min(end, memslot->userspace_addr +
> - (memslot->npages << PAGE_SHIFT));
> - if (hva_start >= hva_end)
> - continue;
> -
> - /*
> - * {gfn(page) | page intersects with [hva_start, hva_end)} =
> - * {gfn_start, gfn_start+1, ..., gfn_end-1}.
> - */
> - gfn = hva_to_gfn_memslot(hva_start, memslot);
> - gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);
> -
> - ret |= handler(kvm, gfn, gfn_end, memslot, data);
> - }
> -
> - return ret;
> -}
> -
> -
> -static int kvm_unmap_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
> - struct kvm_memory_slot *memslot, void *data)
> -{
> - kvm_mips_flush_gpa_pt(kvm, gfn, gfn_end);
> - return 1;
> -}
> -
> -int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end,
> - unsigned flags)
> -{
> - handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, NULL);
> + kvm_mips_flush_gpa_pt(kvm, range->start, range->end);
>
> kvm_mips_callbacks->flush_shadow_all(kvm);
> return 0;
> }
>
> -static int kvm_set_spte_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
> - struct kvm_memory_slot *memslot, void *data)
> +static bool __kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
> {
> - gpa_t gpa = gfn << PAGE_SHIFT;
> - pte_t hva_pte = *(pte_t *)data;
> + gpa_t gpa = range->start << PAGE_SHIFT;
> + pte_t hva_pte = range->pte;
> pte_t *gpa_pte = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
> pte_t old_pte;
>
> if (!gpa_pte)
> - return 0;
> + return false;
>
> /* Mapping may need adjusting depending on memslot flags */
> old_pte = *gpa_pte;
> - if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES && !pte_dirty(old_pte))
> + if (range->slot->flags & KVM_MEM_LOG_DIRTY_PAGES && !pte_dirty(old_pte))
> hva_pte = pte_mkclean(hva_pte);
> - else if (memslot->flags & KVM_MEM_READONLY)
> + else if (range->slot->flags & KVM_MEM_READONLY)
> hva_pte = pte_wrprotect(hva_pte);
>
> set_pte(gpa_pte, hva_pte);
>
> /* Replacing an absent or old page doesn't need flushes */
> if (!pte_present(old_pte) || !pte_young(old_pte))
> - return 0;
> + return false;
>
> /* Pages swapped, aged, moved, or cleaned require flushes */
> return !pte_present(hva_pte) ||
> @@ -526,27 +477,21 @@ static int kvm_set_spte_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
> (pte_dirty(old_pte) && !pte_dirty(hva_pte));
> }
>
> -int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
> +bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
> {
> - unsigned long end = hva + PAGE_SIZE;
> - int ret;
> -
> - ret = handle_hva_to_gpa(kvm, hva, end, &kvm_set_spte_handler, &pte);
> - if (ret)
> + if (__kvm_set_spte_gfn(kvm, range))
> kvm_mips_callbacks->flush_shadow_all(kvm);
> - return 0;
> + return false;
> }
>
> -static int kvm_age_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
> - struct kvm_memory_slot *memslot, void *data)
> +bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
> {
> - return kvm_mips_mkold_gpa_pt(kvm, gfn, gfn_end);
> + return kvm_mips_mkold_gpa_pt(kvm, range->start, range->end);
> }
>
> -static int kvm_test_age_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
> - struct kvm_memory_slot *memslot, void *data)
> +bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
> {
> - gpa_t gpa = gfn << PAGE_SHIFT;
> + gpa_t gpa = range->start << PAGE_SHIFT;
> pte_t *gpa_pte = kvm_mips_pte_for_gpa(kvm, NULL, gpa);
>
> if (!gpa_pte)
> @@ -554,16 +499,6 @@ static int kvm_test_age_hva_handler(struct kvm *kvm, gfn_t gfn, gfn_t gfn_end,
> return pte_young(*gpa_pte);
> }
>
> -int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)
> -{
> - return handle_hva_to_gpa(kvm, start, end, kvm_age_hva_handler, NULL);
> -}
> -
> -int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
> -{
> - return handle_hva_to_gpa(kvm, hva, hva, kvm_test_age_hva_handler, NULL);
> -}
> -
> /**
> * _kvm_mips_map_page_fast() - Fast path GPA fault handler.
> * @vcpu: VCPU pointer.
>
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