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From: Jarkko Sakkinen <jarkko@kernel.org>
To: Paolo Bonzini <pbonzini@redhat.com>,
	qemu-devel@nongnu.org,  seanjc@google.com, kai.huang@intel.com
Cc: Yang Zhong <yang.zhong@intel.com>, eblake@redhat.com
Subject: Re: [PATCH v4 22/33] hostmem-epc: Add the reset interface for EPC backend reset
Date: Mon, 13 Sep 2021 23:17:55 +0300	[thread overview]
Message-ID: <0ec706b694f8e9451452b23c76c8a39155baf357.camel@kernel.org> (raw)
In-Reply-To: <dc8394c5-52a1-573f-36d3-de8bc43973d3@redhat.com>

On Fri, 2021-09-10 at 17:10 +0200, Paolo Bonzini wrote:
> On 19/07/21 13:21, Yang Zhong wrote:
> > +void sgx_memory_backend_reset(HostMemoryBackend *backend, int fd,
> > +                              Error **errp)
> > +{
> > +    MemoryRegion *mr = &backend->mr;
> > +
> > +    mr->enabled = false;
> > +
> > +    /* destroy the old memory region if it exist */
> > +    if (fd > 0 && mr->destructor) {
> > +        mr->destructor(mr);
> > +    }
> > +
> > +    sgx_epc_backend_memory_alloc(backend, errp);
> > +}
> > +
> 
> Jarkko, Sean, Kai,
> 
> this I think is problematic because it has a race window while 
> /dev/sgx_vepc is closed and then reopened.  First, the vEPC space could 
> be exhausted by somebody doing another mmap in the meanwhile.  Second, 
> somebody might (for whatever reason) remove /dev/sgx_vepc while QEMU runs.

1: Why is it a problem that mmap() could fail?

2: Are you speaking about removing device node? If you have succesfully
   mapped /dev/sgx_vepc, that should not have much effect (file refcount).

/Jarkko



  parent reply	other threads:[~2021-09-13 20:18 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-19 11:21 [PATCH v4 00/33] Qemu SGX virtualization Yang Zhong
2021-07-19 11:21 ` [PATCH v4 01/33] memory: Add RAM_PROTECTED flag to skip IOMMU mappings Yang Zhong
2021-07-19 11:21 ` [PATCH v4 02/33] hostmem: Add hostmem-epc as a backend for SGX EPC Yang Zhong
2021-07-19 11:21 ` [PATCH v4 03/33] qom: Add memory-backend-epc ObjectOptions support Yang Zhong
2021-07-19 11:21 ` [PATCH v4 04/33] i386: Add 'sgx-epc' device to expose EPC sections to guest Yang Zhong
2021-09-14  6:36   ` Philippe Mathieu-Daudé
2021-09-16  1:29     ` Yang Zhong
2021-07-19 11:21 ` [PATCH v4 05/33] vl: Add sgx compound properties to expose SGX " Yang Zhong
2021-07-19 11:21 ` [PATCH v4 06/33] i386: Add primary SGX CPUID and MSR defines Yang Zhong
2021-07-19 11:21 ` [PATCH v4 07/33] i386: Add SGX CPUID leaf FEAT_SGX_12_0_EAX Yang Zhong
2021-07-19 11:21 ` [PATCH v4 08/33] i386: Add SGX CPUID leaf FEAT_SGX_12_0_EBX Yang Zhong
2021-07-19 11:21 ` [PATCH v4 09/33] i386: Add SGX CPUID leaf FEAT_SGX_12_1_EAX Yang Zhong
2021-07-19 11:21 ` [PATCH v4 10/33] i386: Add get/set/migrate support for SGX_LEPUBKEYHASH MSRs Yang Zhong
2021-09-14  6:38   ` Philippe Mathieu-Daudé
2021-09-16  6:08     ` Yang Zhong
2021-09-16  6:35       ` Philippe Mathieu-Daudé
2021-07-19 11:21 ` [PATCH v4 11/33] i386: Add feature control MSR dependency when SGX is enabled Yang Zhong
2021-07-19 11:21 ` [PATCH v4 12/33] i386: Update SGX CPUID info according to hardware/KVM/user input Yang Zhong
2021-07-19 11:21 ` [PATCH v4 13/33] i386: kvm: Add support for exposing PROVISIONKEY to guest Yang Zhong
2021-07-19 11:21 ` [PATCH v4 14/33] i386: Propagate SGX CPUID sub-leafs to KVM Yang Zhong
2021-07-19 11:21 ` [PATCH v4 15/33] Adjust min CPUID level to 0x12 when SGX is enabled Yang Zhong
2021-07-19 11:21 ` [PATCH v4 16/33] hw/i386/fw_cfg: Set SGX bits in feature control fw_cfg accordingly Yang Zhong
2021-07-19 11:21 ` [PATCH v4 17/33] hw/i386/pc: Account for SGX EPC sections when calculating device memory Yang Zhong
2021-07-19 11:21 ` [PATCH v4 18/33] i386/pc: Add e820 entry for SGX EPC section(s) Yang Zhong
2021-07-19 11:21 ` [PATCH v4 19/33] i386: acpi: Add SGX EPC entry to ACPI tables Yang Zhong
2021-07-19 11:21 ` [PATCH v4 20/33] q35: Add support for SGX EPC Yang Zhong
2021-07-19 11:21 ` [PATCH v4 21/33] i440fx: " Yang Zhong
2021-07-19 11:21 ` [PATCH v4 22/33] hostmem-epc: Add the reset interface for EPC backend reset Yang Zhong
2021-09-10 15:10   ` Paolo Bonzini
2021-09-10 15:34     ` Sean Christopherson
2021-09-10 17:09       ` Paolo Bonzini
2021-09-10 17:34         ` Sean Christopherson
2021-09-10 19:51           ` Paolo Bonzini
2021-09-10 20:21             ` Sean Christopherson
2021-09-10 20:57               ` Paolo Bonzini
2021-09-13 20:17     ` Jarkko Sakkinen [this message]
2021-09-13 20:37       ` Sean Christopherson
2021-09-13 21:23         ` Jarkko Sakkinen
2021-07-19 11:21 ` [PATCH v4 23/33] sgx-epc: Add the reset interface for sgx-epc virt device Yang Zhong
2021-09-10 15:13   ` Paolo Bonzini
2021-09-14  6:53   ` Philippe Mathieu-Daudé
2021-09-15 11:33     ` Yang Zhong
2021-07-19 11:21 ` [PATCH v4 24/33] sgx-epc: Avoid bios reset during sgx epc initialization Yang Zhong
2021-07-19 11:21 ` [PATCH v4 25/33] hostmem-epc: Make prealloc consistent with qemu cmdline during reset Yang Zhong
2021-07-19 11:21 ` [PATCH v4 26/33] qmp: Add query-sgx command Yang Zhong
2021-07-19 11:21 ` [PATCH v4 27/33] hmp: Add 'info sgx' command Yang Zhong
2021-07-19 11:21 ` [PATCH v4 28/33] i386: Add sgx_get_info() interface Yang Zhong
2021-07-19 11:21 ` [PATCH v4 29/33] bitops: Support 32 and 64 bit mask macro Yang Zhong
2021-07-19 11:21 ` [PATCH v4 30/33] qmp: Add the qmp_query_sgx_capabilities() Yang Zhong
2021-07-19 11:21 ` [PATCH v4 31/33] Kconfig: Add CONFIG_SGX support Yang Zhong
2021-07-19 11:21 ` [PATCH v4 32/33] sgx-epc: Add the fill_device_info() callback support Yang Zhong
2021-07-19 11:21 ` [PATCH v4 33/33] doc: Add the SGX doc Yang Zhong
2021-07-28 15:57 ` [PATCH v4 00/33] Qemu SGX virtualization Paolo Bonzini
2021-07-29 12:27   ` Yang Zhong
2021-09-06 13:13 ` Paolo Bonzini
2021-09-07  2:24   ` Yang Zhong
2021-09-07  9:51   ` Yang Zhong
2021-09-07 13:35     ` Jarkko Sakkinen
2021-09-08  6:00     ` Paolo Bonzini
2021-09-14  6:51 ` Philippe Mathieu-Daudé
2021-09-15 12:24   ` Yang Zhong

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