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From: Kai Huang <kai.huang@intel.com>
To: Sean Christopherson <seanjc@google.com>
Cc: kvm@vger.kernel.org, linux-sgx@vger.kernel.org,
	pbonzini@redhat.com, bp@alien8.de, jarkko@kernel.org,
	dave.hansen@intel.com, luto@kernel.org,
	rick.p.edgecombe@intel.com, haitao.huang@intel.com
Subject: Re: [PATCH v4 07/11] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions
Date: Thu, 8 Apr 2021 10:16:38 +1200	[thread overview]
Message-ID: <20210408101638.6ce24b50924425308ee7c616@intel.com> (raw)
In-Reply-To: <YG4sh72soS6JC107@google.com>

On Wed, 7 Apr 2021 22:04:55 +0000 Sean Christopherson wrote:
> On Thu, Apr 08, 2021, Kai Huang wrote:
> > On Wed, 7 Apr 2021 21:52:50 +0000 Sean Christopherson wrote:
> > > On Thu, Apr 08, 2021, Kai Huang wrote:
> > > > +	/*
> > > > +	 * Copy contents into kernel memory to prevent TOCTOU attack. E.g. the
> > > > +	 * guest could do ECREATE w/ SECS.SGX_ATTR_PROVISIONKEY=0, and
> > > > +	 * simultaneously set SGX_ATTR_PROVISIONKEY to bypass the check to
> > > > +	 * enforce restriction of access to the PROVISIONKEY.
> > > > +	 */
> > > > +	contents = (struct sgx_secs *)__get_free_page(GFP_KERNEL);
> > > 
> > > This should use GFP_KERNEL_ACCOUNT.
> > 
> > May I ask why? The page is only a temporary allocation, it will be freed before
> > this function returns. I guess a 4K page is OK?
> 
> A hard limit should not be violated, even temporarily.  This is also per vCPU,
> e.g. a 256 vCPU VM could go 1mb over the limit.  

OK. Will change in next version.

  reply	other threads:[~2021-04-07 22:16 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-07 20:49 [PATCH v4 00/11] KVM SGX virtualization support (KVM part) Kai Huang
2021-04-07 20:49 ` [PATCH v4 01/11] KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX) Kai Huang
2021-04-07 20:49 ` [PATCH v4 02/11] KVM: x86: Define new #PF SGX error code bit Kai Huang
2021-04-07 20:49 ` [PATCH v4 03/11] KVM: x86: Add support for reverse CPUID lookup of scattered features Kai Huang
2021-04-07 20:49 ` [PATCH v4 04/11] KVM: x86: Add reverse-CPUID lookup support for scattered SGX features Kai Huang
2021-04-07 20:49 ` [PATCH v4 05/11] KVM: VMX: Add basic handling of VM-Exit from SGX enclave Kai Huang
2021-04-07 20:49 ` [PATCH v4 06/11] KVM: VMX: Frame in ENCLS handler for SGX virtualization Kai Huang
2021-04-07 22:16   ` Sean Christopherson
2021-04-07 22:33     ` Kai Huang
2021-04-07 22:35       ` Sean Christopherson
2021-04-07 22:44         ` Kai Huang
2021-04-07 22:47           ` Sean Christopherson
2021-04-07 22:59             ` Kai Huang
2021-04-07 20:49 ` [PATCH v4 07/11] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions Kai Huang
2021-04-07 21:52   ` Sean Christopherson
2021-04-07 21:58     ` Kai Huang
2021-04-07 22:04       ` Sean Christopherson
2021-04-07 22:16         ` Kai Huang [this message]
2021-04-07 22:10   ` Sean Christopherson
2021-04-07 22:15     ` Kai Huang
2021-04-07 20:49 ` [PATCH v4 08/11] KVM: VMX: Add emulation of SGX Launch Control LE hash MSRs Kai Huang
2021-04-07 20:49 ` [PATCH v4 09/11] KVM: VMX: Add ENCLS[EINIT] handler to support SGX Launch Control (LC) Kai Huang
2021-04-07 20:49 ` [PATCH v4 10/11] KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC Kai Huang
2021-04-07 20:49 ` [PATCH v4 11/11] KVM: x86: Add capability to grant VM access to privileged SGX attribute Kai Huang
2021-04-07 23:08 ` [PATCH v4 00/11] KVM SGX virtualization support (KVM part) Kai Huang

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