From: Steven Price <steven.price@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>, Will Deacon <will@kernel.org>,
James Morse <James.Morse@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki Poulose <Suzuki.Poulose@arm.com>,
"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Dave P Martin <Dave.Martin@arm.com>,
Mark Rutland <Mark.Rutland@arm.com>,
Thomas Gleixner <tglx@linutronix.de>
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
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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