From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Yang Zhong <yang.zhong@intel.com>,
Jarkko Sakkinen <jarkko@kernel.org>,
"Blake, Eric" <eblake@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>,
"Huang, Kai" <kai.huang@intel.com>
Subject: Re: [PATCH v4 22/33] hostmem-epc: Add the reset interface for EPC backend reset
Date: Fri, 10 Sep 2021 22:57:25 +0200 [thread overview]
Message-ID: <CABgObfZh3pzktRbZf0+kvz=Vf0kbHTCGH=HK=DwyFsTQMbzfQA@mail.gmail.com> (raw)
In-Reply-To: <YTu+LG8v6eOhQBzi@google.com>
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Il ven 10 set 2021, 22:21 Sean Christopherson <seanjc@google.com> ha
scritto:
> > It's also possible that QEMU handles failure, but the kernel does two
> > passes; then QEMU can just do two passes. The kernel will overall do
> four
> > passes, but:
> >
> > 1) the second (SECS pinned by children in the same vEPC) would be cheaper
> > than a full second pass
>
> The problem is that this would require a list_head (or temp allocations)
> to track
> the SECS pages that failed the first time 'round. For vEPC destruction,
> the kernel
> can use sgx_epc_page.list because it can take the pages off the
> active/allocated
> list, but that's not an option in this case because the
> presumably-upcoming EPC
> cgroup needs to keep pages on the list to handle OOM.
>
Good point, so yeah: let's go for a ioctl that does full removal, returning
the number of failures. I will try and cobble up a patch unless Kai beats
me to it.
Thanks for the quick discussion!
Paolo
> The kernel's ioctl/syscall/whatever could return the number of pages that
> were
> not freed, or maybe just -EAGAIN, and userspace could use that to know it
> needs
> to do another reset to free everything.
>
> My thought for QEMU was to do (bad pseudocode):
>
> /* Retry to EREMOVE pinned SECS pages if necessary. */
> ret = ioctl(SGX_VEPC_RESET, ...);
> if (ret)
> ret = ioctl(SGX_VEPC_RESET, ...);
>
> /*
> * Tag the VM as needed yet another round of resets to ERMOVE SECS
> pages
> * that were pinned across vEPC sections.
> */
> vm->sgx_epc_final_reset_needed = !!ret;
>
> > 2) the fourth would actually do nothing, because there would be no pages
> > failing the EREMOV'al.
> >
> > A hypothetical other SGX client that only uses one vEPC will do the right
> > thing with a single pass.
>
>
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next prev parent reply other threads:[~2021-09-10 20:58 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 [this message]
2021-09-13 20:17 ` Jarkko Sakkinen
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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