From: Kai Huang <kai.huang@intel.com>
To: Kai Huang <kai.huang@intel.com>
Cc: <kvm@vger.kernel.org>, <x86@kernel.org>,
<linux-sgx@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<seanjc@google.com>, <jarkko@kernel.org>, <luto@kernel.org>,
<dave.hansen@intel.com>, <rick.p.edgecombe@intel.com>,
<haitao.huang@intel.com>, <pbonzini@redhat.com>, <bp@alien8.de>,
<tglx@linutronix.de>, <mingo@redhat.com>, <hpa@zytor.com>
Subject: Re: [PATCH v2 03/25] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page()
Date: Wed, 10 Mar 2021 22:35:10 +1300 [thread overview]
Message-ID: <20210310223510.f0f3bbe50f3c6d21b00ac5a5@intel.com> (raw)
In-Reply-To: <e1ca4131bc9f98cf50a1200efcf46080d6512fe7.1615250634.git.kai.huang@intel.com>
On Tue, 9 Mar 2021 14:39:01 +1300 Kai Huang wrote:
> From: Jarkko Sakkinen <jarkko@kernel.org>
>
> EREMOVE takes a page and removes any association between that page and
> an enclave. It must be run on a page before it can be added into
> another enclave. Currently, EREMOVE is run as part of pages being freed
> into the SGX page allocator. It is not expected to fail.
>
> KVM does not track how guest pages are used, which means that SGX
> virtualization use of EREMOVE might fail.
>
> Break out the EREMOVE call from the SGX page allocator. This will allow
> the SGX virtualization code to use the allocator directly. (SGX/KVM
> will also introduce a more permissive EREMOVE helper).
>
> Implement original sgx_free_epc_page() as sgx_encl_free_epc_page() to be
> more specific that it is used to free EPC page assigned to one enclave.
> Print an error message when EREMOVE fails to explicitly call out EPC
> page is leaked, and requires machine reboot to get leaked pages back.
>
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> Co-developed-by: Kai Huang <kai.huang@intel.com>
> Signed-off-by: Kai Huang <kai.huang@intel.com>
> ---
> v1->v2:
>
> - Merge original WARN() and pr_err_once() into one single WARN(), suggested
> by Sean.
>
> ---
> arch/x86/kernel/cpu/sgx/encl.c | 27 ++++++++++++++++++++++++---
> arch/x86/kernel/cpu/sgx/main.c | 12 ++++--------
> 2 files changed, 28 insertions(+), 11 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
> index 7449ef33f081..dcbcf840c522 100644
> --- a/arch/x86/kernel/cpu/sgx/encl.c
> +++ b/arch/x86/kernel/cpu/sgx/encl.c
> @@ -381,6 +381,27 @@ const struct vm_operations_struct sgx_vm_ops = {
> .access = sgx_vma_access,
> };
>
> +static void sgx_encl_free_epc_page(struct sgx_epc_page *epc_page)
> +{
> + int ret;
> +
> + WARN_ON_ONCE(epc_page->flags & SGX_EPC_PAGE_RECLAIMER_TRACKED);
> +
> + /*
> + * Give a message to remind EPC page is leaked when EREMOVE fails,
> + * and requires machine reboot to get leaked pages back. This can
> + * be improved in future by adding stats of leaked pages, etc.
> + */
> +#define EREMOVE_ERROR_MESSAGE \
> + "EREMOVE returned %d (0x%x). EPC page leaked. Reboot required to retrieve leaked pages."
> + ret = __eremove(sgx_get_epc_virt_addr(epc_page));
> + if (WARN_ONCE(ret, EREMOVE_ERROR_MESSAGE, ret, ret))
> + return;
> +#undef EREMOVE_ERROR_MESSAGE
> +
> + sgx_free_epc_page(epc_page);
> +}
> +
> /**
> * sgx_encl_release - Destroy an enclave instance
> * @kref: address of a kref inside &sgx_encl
> @@ -404,7 +425,7 @@ void sgx_encl_release(struct kref *ref)
> if (sgx_unmark_page_reclaimable(entry->epc_page))
> continue;
>
> - sgx_free_epc_page(entry->epc_page);
> + sgx_encl_free_epc_page(entry->epc_page);
> encl->secs_child_cnt--;
> entry->epc_page = NULL;
> }
> @@ -415,7 +436,7 @@ void sgx_encl_release(struct kref *ref)
> xa_destroy(&encl->page_array);
>
> if (!encl->secs_child_cnt && encl->secs.epc_page) {
> - sgx_free_epc_page(encl->secs.epc_page);
> + sgx_encl_free_epc_page(entry->epc_page);
Sorry. A mistake during copy/paste. Will fix.
> encl->secs.epc_page = NULL;
> }
>
> @@ -423,7 +444,7 @@ void sgx_encl_release(struct kref *ref)
> va_page = list_first_entry(&encl->va_pages, struct sgx_va_page,
> list);
> list_del(&va_page->list);
> - sgx_free_epc_page(va_page->epc_page);
> + sgx_encl_free_epc_page(entry->epc_page);
Sorry. A mistake during copy/paste. Will fix.
> kfree(va_page);
> }
>
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index 8df81a3ed945..44fe91a5bfb3 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -598,18 +598,14 @@ struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim)
> * sgx_free_epc_page() - Free an EPC page
> * @page: an EPC page
> *
> - * Call EREMOVE for an EPC page and insert it back to the list of free pages.
> + * Put the EPC page back to the list of free pages. It's the caller's
> + * responsibility to make sure that the page is in uninitialized state. In other
> + * words, do EREMOVE, EWB or whatever operation is necessary before calling
> + * this function.
> */
> void sgx_free_epc_page(struct sgx_epc_page *page)
> {
> struct sgx_epc_section *section = &sgx_epc_sections[page->section];
> - int ret;
> -
> - WARN_ON_ONCE(page->flags & SGX_EPC_PAGE_RECLAIMER_TRACKED);
> -
> - ret = __eremove(sgx_get_epc_virt_addr(page));
> - if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret))
> - return;
>
> spin_lock(§ion->lock);
> list_add_tail(&page->list, §ion->page_list);
> --
> 2.29.2
>
next prev parent reply other threads:[~2021-03-10 9:36 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-09 1:38 [PATCH v2 00/25] KVM SGX virtualization support Kai Huang
2021-03-09 1:38 ` [PATCH v2 01/25] x86/cpufeatures: Make SGX_LC feature bit depend on SGX bit Kai Huang
2021-03-12 21:05 ` Sean Christopherson
2021-03-09 1:39 ` [PATCH v2 02/25] x86/cpufeatures: Add SGX1 and SGX2 sub-features Kai Huang
2021-03-12 21:10 ` Sean Christopherson
2021-03-09 1:39 ` [PATCH v2 03/25] x86/sgx: Wipe out EREMOVE from sgx_free_epc_page() Kai Huang
2021-03-10 9:35 ` Kai Huang [this message]
2021-03-11 2:01 ` [PATCH v3 " Kai Huang
2021-03-12 21:21 ` Sean Christopherson
2021-03-13 10:45 ` Jarkko Sakkinen
2021-03-15 7:12 ` Kai Huang
2021-03-15 13:18 ` Jarkko Sakkinen
2021-03-15 13:19 ` Jarkko Sakkinen
2021-03-15 20:29 ` Kai Huang
2021-03-15 22:59 ` Jarkko Sakkinen
2021-03-15 23:50 ` Kai Huang
2021-03-15 23:11 ` Jarkko Sakkinen
2021-03-09 1:39 ` [PATCH v2 04/25] x86/sgx: Add SGX_CHILD_PRESENT hardware error code Kai Huang
2021-03-09 1:39 ` [PATCH v2 05/25] x86/sgx: Introduce virtual EPC for use by KVM guests Kai Huang
2021-03-09 1:39 ` [PATCH v2 06/25] x86/cpu/intel: Allow SGX virtualization without Launch Control support Kai Huang
2021-03-12 21:33 ` Sean Christopherson
2021-03-09 1:39 ` [PATCH v2 07/25] x86/sgx: Initialize virtual EPC driver even when SGX driver is disabled Kai Huang
2021-03-12 21:44 ` Sean Christopherson
2021-03-13 19:05 ` Jarkko Sakkinen
2021-03-13 19:07 ` Jarkko Sakkinen
2021-03-14 15:25 ` Jarkko Sakkinen
2021-03-14 15:27 ` Jarkko Sakkinen
2021-03-15 3:13 ` Kai Huang
2021-03-15 13:04 ` Jarkko Sakkinen
2021-03-15 13:51 ` Jarkko Sakkinen
2021-03-15 20:48 ` Kai Huang
2021-03-15 23:05 ` Jarkko Sakkinen
2021-03-15 23:08 ` Jarkko Sakkinen
2021-03-15 23:49 ` Kai Huang
2021-03-16 12:44 ` Jarkko Sakkinen
2021-03-16 1:13 ` Sean Christopherson
2021-03-16 12:46 ` Jarkko Sakkinen
2021-03-18 0:04 ` Kai Huang
2021-03-09 1:39 ` [PATCH v2 08/25] x86/sgx: Expose SGX architectural definitions to the kernel Kai Huang
2021-03-12 21:58 ` Sean Christopherson
2021-03-15 3:36 ` Kai Huang
2021-03-09 1:39 ` [PATCH v2 09/25] x86/sgx: Move ENCLS leaf definitions to sgx.h Kai Huang
2021-03-09 1:39 ` [PATCH v2 10/25] x86/sgx: Add SGX2 ENCLS leaf definitions (EAUG, EMODPR and EMODT) Kai Huang
2021-03-09 1:39 ` [PATCH v2 11/25] x86/sgx: Add encls_faulted() helper Kai Huang
2021-03-09 1:39 ` [PATCH v2 12/25] x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRs Kai Huang
2021-03-09 1:39 ` [PATCH v2 13/25] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM Kai Huang
2021-03-15 4:08 ` Kai Huang
2021-03-09 1:39 ` [PATCH v2 14/25] x86/sgx: Move provisioning device creation out of SGX driver Kai Huang
2021-03-09 1:40 ` [PATCH v2 15/25] KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX) Kai Huang
2021-03-09 1:40 ` [PATCH v2 16/25] KVM: x86: Define new #PF SGX error code bit Kai Huang
2021-03-09 1:40 ` [PATCH v2 17/25] KVM: x86: Add support for reverse CPUID lookup of scattered features Kai Huang
2021-03-09 1:40 ` [PATCH v2 18/25] KVM: x86: Add reverse-CPUID lookup support for scattered SGX features Kai Huang
2021-03-09 1:40 ` [PATCH v2 19/25] KVM: VMX: Add basic handling of VM-Exit from SGX enclave Kai Huang
2021-03-09 1:40 ` [PATCH v2 20/25] KVM: VMX: Frame in ENCLS handler for SGX virtualization Kai Huang
2021-03-09 1:40 ` [PATCH v2 21/25] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions Kai Huang
2021-03-09 1:40 ` [PATCH v2 22/25] KVM: VMX: Add emulation of SGX Launch Control LE hash MSRs Kai Huang
2021-03-09 1:40 ` [PATCH v2 23/25] KVM: VMX: Add ENCLS[EINIT] handler to support SGX Launch Control (LC) Kai Huang
2021-03-09 1:40 ` [PATCH v2 24/25] KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC Kai Huang
2021-03-09 1:41 ` [PATCH v2 25/25] KVM: x86: Add capability to grant VM access to privileged SGX attribute Kai Huang
2021-03-09 9:30 ` [PATCH v2 00/25] KVM SGX virtualization support Borislav Petkov
2021-03-09 18:08 ` Kai Huang
2021-03-09 18:49 ` Paolo Bonzini
2021-03-12 22:04 ` Sean Christopherson
2021-03-13 4:30 ` Kai Huang
2021-03-10 9:27 ` Kai Huang
2021-03-10 13:29 ` Borislav Petkov
2021-03-11 2:05 ` Kai Huang
2021-03-10 18:01 ` Jarkko Sakkinen
2021-03-10 20:44 ` Kai Huang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210310223510.f0f3bbe50f3c6d21b00ac5a5@intel.com \
--to=kai.huang@intel.com \
--cc=bp@alien8.de \
--cc=dave.hansen@intel.com \
--cc=haitao.huang@intel.com \
--cc=hpa@zytor.com \
--cc=jarkko@kernel.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-sgx@vger.kernel.org \
--cc=luto@kernel.org \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=rick.p.edgecombe@intel.com \
--cc=seanjc@google.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).