From: Fuad Tabba <tabba@google.com>
To: Steven Price <steven.price@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
qemu-devel@nongnu.org, Dave Martin <Dave.Martin@arm.com>,
Juan Quintela <quintela@redhat.com>,
Richard Henderson <richard.henderson@linaro.org>,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v17 4/6] KVM: arm64: Expose KVM_ARM_CAP_MTE
Date: Tue, 22 Jun 2021 09:07:51 +0100 [thread overview]
Message-ID: <CA+EHjTzuduzTcJo+jjVzVAVUB4i3Nr3mki4jyiNW9K=pr-HPYA@mail.gmail.com> (raw)
In-Reply-To: <20210621111716.37157-5-steven.price@arm.com>
Hi,
On Mon, Jun 21, 2021 at 12:18 PM Steven Price <steven.price@arm.com> wrote:
>
> It's now safe for the VMM to enable MTE in a guest, so expose the
> capability to user space.
>
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
> arch/arm64/kvm/arm.c | 9 +++++++++
> arch/arm64/kvm/reset.c | 4 ++++
> arch/arm64/kvm/sys_regs.c | 3 +++
> 3 files changed, 16 insertions(+)
>
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index e720148232a0..28ce26a68f09 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -93,6 +93,12 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
> r = 0;
> kvm->arch.return_nisv_io_abort_to_user = true;
> break;
> + case KVM_CAP_ARM_MTE:
> + if (!system_supports_mte() || kvm->created_vcpus)
> + return -EINVAL;
> + r = 0;
> + kvm->arch.mte_enabled = true;
> + break;
> default:
> r = -EINVAL;
> break;
> @@ -237,6 +243,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> */
> r = 1;
> break;
> + case KVM_CAP_ARM_MTE:
> + r = system_supports_mte();
> + break;
> case KVM_CAP_STEAL_TIME:
> r = kvm_arm_pvtime_supported();
> break;
> diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
> index d37ebee085cf..9e6922b9503a 100644
> --- a/arch/arm64/kvm/reset.c
> +++ b/arch/arm64/kvm/reset.c
> @@ -244,6 +244,10 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu)
> switch (vcpu->arch.target) {
> default:
> if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) {
> + if (vcpu->kvm->arch.mte_enabled) {
> + ret = -EINVAL;
> + goto out;
> + }
> pstate = VCPU_RESET_PSTATE_SVC;
> } else {
> pstate = VCPU_RESET_PSTATE_EL1;
nit: I was wondering whether this check would be better suited in
kvm_vcpu_set_target, rather than here (kvm_reset_vcpu). kvm_reset_vcpu
is called by kvm_vcpu_set_target, but kvm_vcpu_set_target is where
checking for supported features happens. It might be better to group
all such checks together. I don't think that there is any risk of this
feature being toggled by the other call path to kvm_reset_vcpu (via
check_vcpu_requests).
Cheers,
/fuad
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 5c75b24eae21..f6f126eb6ac1 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -1312,6 +1312,9 @@ static bool access_ccsidr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> static unsigned int mte_visibility(const struct kvm_vcpu *vcpu,
> const struct sys_reg_desc *rd)
> {
> + if (kvm_has_mte(vcpu->kvm))
> + return 0;
> +
> return REG_HIDDEN;
> }
>
> --
> 2.20.1
>
> _______________________________________________
> kvmarm mailing list
> kvmarm@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
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next prev parent reply other threads:[~2021-06-22 8:10 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-21 11:17 [PATCH v17 0/6] MTE support for KVM guest Steven Price
2021-06-21 11:17 ` [PATCH v17 1/6] arm64: mte: Sync tags for pages where PTE is untagged Steven Price
2021-06-21 11:17 ` [PATCH v17 2/6] KVM: arm64: Introduce MTE VM feature Steven Price
2021-06-21 17:00 ` Fuad Tabba
2021-06-22 11:29 ` Marc Zyngier
2021-06-21 11:17 ` [PATCH v17 3/6] KVM: arm64: Save/restore MTE registers Steven Price
2021-06-22 9:46 ` Fuad Tabba
2021-06-21 11:17 ` [PATCH v17 4/6] KVM: arm64: Expose KVM_ARM_CAP_MTE Steven Price
2021-06-22 8:07 ` Fuad Tabba [this message]
2021-06-22 8:48 ` Marc Zyngier
2021-06-21 11:17 ` [PATCH v17 5/6] KVM: arm64: ioctl to fetch/store tags in a guest Steven Price
2021-06-22 8:56 ` Fuad Tabba
2021-06-22 10:25 ` Marc Zyngier
2021-06-22 10:56 ` Fuad Tabba
2021-06-23 14:07 ` Steven Price
2021-06-24 13:35 ` Marc Zyngier
2021-06-24 13:42 ` Steven Price
2021-06-21 11:17 ` [PATCH v17 6/6] KVM: arm64: Document MTE capability and ioctl Steven Price
2021-06-22 9:42 ` Fuad Tabba
2021-06-22 10:35 ` Marc Zyngier
2021-06-22 10:41 ` Fuad Tabba
2021-06-22 14:21 ` [PATCH v17 0/6] MTE support for KVM guest Marc Zyngier
2021-06-23 14:09 ` Steven Price
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