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Message-ID: <CA+EHjTwV2mXOXMF7u+pVaSqvJ2c-iPGMxPBhrj7oZrm+oaAi3A@mail.gmail.com>
Date: Tue, 10 Dec 2024 15:11:53 +0000
From: Fuad Tabba <tabba@...gle.com>
To: Quentin Perret <qperret@...gle.com>
Cc: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>,
Joey Gouly <joey.gouly@....com>, Suzuki K Poulose <suzuki.poulose@....com>,
Zenghui Yu <yuzenghui@...wei.com>, Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>, Vincent Donnefort <vdonnefort@...gle.com>,
Sebastian Ene <sebastianene@...gle.com>, linux-arm-kernel@...ts.infradead.org,
kvmarm@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 14/18] KVM: arm64: Introduce __pkvm_host_test_clear_young_guest()
Hi Quentin,
On Tue, 3 Dec 2024 at 10:38, Quentin Perret <qperret@...gle.com> wrote:
>
> Plumb the kvm_stage2_test_clear_young() callback into pKVM for
> non-protected guest. It will be later be called from MMU notifiers.
>
> Signed-off-by: Quentin Perret <qperret@...gle.com>
> ---
> arch/arm64/include/asm/kvm_asm.h | 1 +
> arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 1 +
> arch/arm64/kvm/hyp/nvhe/hyp-main.c | 25 +++++++++++++++++++
> arch/arm64/kvm/hyp/nvhe/mem_protect.c | 19 ++++++++++++++
> 4 files changed, 46 insertions(+)
>
> diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
> index 4d7d20ea03df..cb676017d591 100644
> --- a/arch/arm64/include/asm/kvm_asm.h
> +++ b/arch/arm64/include/asm/kvm_asm.h
> @@ -69,6 +69,7 @@ enum __kvm_host_smccc_func {
> __KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_guest,
> __KVM_HOST_SMCCC_FUNC___pkvm_host_relax_guest_perms,
> __KVM_HOST_SMCCC_FUNC___pkvm_host_wrprotect_guest,
> + __KVM_HOST_SMCCC_FUNC___pkvm_host_test_clear_young_guest,
> __KVM_HOST_SMCCC_FUNC___kvm_adjust_pc,
> __KVM_HOST_SMCCC_FUNC___kvm_vcpu_run,
> __KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context,
> diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
> index 8658b5932473..554ce31882e6 100644
> --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
> +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
> @@ -43,6 +43,7 @@ int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum k
> int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm);
> int __pkvm_host_relax_guest_perms(u64 gfn, enum kvm_pgtable_prot prot, struct pkvm_hyp_vcpu *vcpu);
> int __pkvm_host_wrprotect_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm);
> +int __pkvm_host_test_clear_young_guest(u64 gfn, bool mkold, struct pkvm_hyp_vm *vm);
While I'm piling on the function names/parameters, some functions have
_guest as a postfix at the end (e.g., this one), others have it in the
middle (__pkvm_host_relax_guest_perms). I guess
__pkvm_host_relax_guest_perms is the odd one out. Could you rename it?
Cheers,
/fuad
> bool addr_is_memory(phys_addr_t phys);
> int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot);
> diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
> index 3feaf2119e51..67cb6e284180 100644
> --- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
> +++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
> @@ -309,6 +309,30 @@ static void handle___pkvm_host_wrprotect_guest(struct kvm_cpu_context *host_ctxt
> cpu_reg(host_ctxt, 1) = ret;
> }
>
> +static void handle___pkvm_host_test_clear_young_guest(struct kvm_cpu_context *host_ctxt)
> +{
> + DECLARE_REG(pkvm_handle_t, handle, host_ctxt, 1);
> + DECLARE_REG(u64, gfn, host_ctxt, 2);
> + DECLARE_REG(bool, mkold, host_ctxt, 3);
> + struct pkvm_hyp_vm *hyp_vm;
> + int ret = -EINVAL;
> +
> + if (!is_protected_kvm_enabled())
> + goto out;
> +
> + hyp_vm = get_pkvm_hyp_vm(handle);
> + if (!hyp_vm)
> + goto out;
> + if (pkvm_hyp_vm_is_protected(hyp_vm))
> + goto put_hyp_vm;
> +
> + ret = __pkvm_host_test_clear_young_guest(gfn, mkold, hyp_vm);
> +put_hyp_vm:
> + put_pkvm_hyp_vm(hyp_vm);
> +out:
> + cpu_reg(host_ctxt, 1) = ret;
> +}
> +
> static void handle___kvm_adjust_pc(struct kvm_cpu_context *host_ctxt)
> {
> DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1);
> @@ -522,6 +546,7 @@ static const hcall_t host_hcall[] = {
> HANDLE_FUNC(__pkvm_host_unshare_guest),
> HANDLE_FUNC(__pkvm_host_relax_guest_perms),
> HANDLE_FUNC(__pkvm_host_wrprotect_guest),
> + HANDLE_FUNC(__pkvm_host_test_clear_young_guest),
> HANDLE_FUNC(__kvm_adjust_pc),
> HANDLE_FUNC(__kvm_vcpu_run),
> HANDLE_FUNC(__kvm_flush_vm_context),
> diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> index 89312d7cde2a..0e064a7ed7c4 100644
> --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
> @@ -1522,3 +1522,22 @@ int __pkvm_host_wrprotect_guest(u64 gfn, struct pkvm_hyp_vm *vm)
>
> return ret;
> }
> +
> +int __pkvm_host_test_clear_young_guest(u64 gfn, bool mkold, struct pkvm_hyp_vm *vm)
> +{
> + u64 ipa = hyp_pfn_to_phys(gfn);
> + u64 phys;
> + int ret;
> +
> + host_lock_component();
> + guest_lock_component(vm);
> +
> + ret = __check_host_unshare_guest(vm, &phys, ipa);
> + if (!ret)
> + ret = kvm_pgtable_stage2_test_clear_young(&vm->pgt, ipa, PAGE_SIZE, mkold);
> +
> + guest_unlock_component(vm);
> + host_unlock_component();
> +
> + return ret;
> +}
> --
> 2.47.0.338.g60cca15819-goog
>
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