From: Steven Price <steven.price@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Dave P Martin <Dave.Martin@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>,
"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>
Subject: Re: [RFC PATCH 2/2] arm64: kvm: Introduce MTE VCPU feature
Date: Wed, 17 Jun 2020 16:34:13 +0100 [thread overview]
Message-ID: <9d4ef6cf-2333-83b8-c555-e70b99b95b28@arm.com> (raw)
In-Reply-To: <20200617143809.GF5388@gaia>
On 17/06/2020 15:38, Catalin Marinas wrote:
> On Wed, Jun 17, 2020 at 01:38:44PM +0100, Steven Price wrote:
>> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
>> index e3b9ee268823..040a7fffaa93 100644
>> --- a/virt/kvm/arm/mmu.c
>> +++ b/virt/kvm/arm/mmu.c
>> @@ -1783,6 +1783,17 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>> vma_pagesize = PMD_SIZE;
>> }
>>
>> + if (system_supports_mte() && kvm->arch.vcpu_has_mte) {
>> + /*
>> + * VM will be able to see the page's tags, so we must ensure
>> + * they have been initialised.
>> + */
>> + struct page *page = pfn_to_page(pfn);
>> +
>> + if (!test_and_set_bit(PG_mte_tagged, &page->flags))
>> + mte_clear_page_tags(page_address(page), page_size(page));
>> + }
>
> Are all the guest pages always mapped via a Stage 2 fault? It may be
> better if we did that via kvm_set_spte_hva().
>
I was under the impression that pages are always faulted into the stage
2, but I have to admit I'm not 100% sure about that.
kvm_set_spte_hva() may be more appropriate, although on first look I
don't understand how that function deals with huge pages. Is it actually
called for normal mappings or only for changes due to the likes of KSM?
Steve
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next prev parent reply other threads:[~2020-06-17 15:34 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-17 12:38 [RFC PATCH 0/2] MTE support for KVM guest Steven Price
2020-06-17 12:38 ` [RFC PATCH 1/2] arm64: kvm: Save/restore MTE registers Steven Price
2020-06-17 14:05 ` Catalin Marinas
2020-06-18 10:43 ` Steven Price
2020-06-17 12:38 ` [RFC PATCH 2/2] arm64: kvm: Introduce MTE VCPU feature Steven Price
2020-06-17 14:38 ` Catalin Marinas
2020-06-17 15:34 ` Steven Price [this message]
2020-06-26 16:40 ` James Morse
2020-06-23 17:48 ` [RFC PATCH 0/2] MTE support for KVM guest Catalin Marinas
2020-06-24 11:16 ` Steven Price
2020-06-24 14:21 ` Catalin Marinas
2020-06-24 14:59 ` Steven Price
2020-06-24 16:24 ` Catalin Marinas
2020-06-26 17:24 ` James Morse
2020-06-23 18:05 ` Peter Maydell
2020-06-24 9:38 ` Catalin Marinas
2020-06-24 10:34 ` Dave Martin
2020-06-24 11:03 ` Steven Price
2020-06-24 11:09 ` Catalin Marinas
2020-06-24 11:18 ` Steven Price
2020-06-24 11:52 ` Catalin Marinas
2020-06-24 13:16 ` Peter Maydell
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