Messages in this thread Patch in this message | | | Date | Wed, 28 Jul 2021 17:42:08 -0700 | From | "Luck, Tony" <> | Subject | Re: [PATCH v3 1/7] x86/sgx: Provide indication of life-cycle of EPC pages |
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On Thu, Jul 29, 2021 at 12:07:08AM +0000, Sean Christopherson wrote: > On Wed, Jul 28, 2021, Luck, Tony wrote: > > > - epc_page = sgx_alloc_epc_page(NULL, true); > > > + epc_page = sgx_alloc_epc_page(va_page, true); > > > > Providing a real value for the owner seems much better than all the hacks > > to invent a value to use instead of NULL. > > > > Can you add a "Signed-off-by"? Then I'll replace my part 0001 with your version.
My commit comment (updated to match how the code actually changed). Sean's code.
N.B. I added the kernel doc entry for the new argument to sgx_alloc_va_page()
+ * @va_page: struct sgx_va_page connected to this VA page
If you have something better, then I will swap that line out too.
-Tony
From: Sean Christopherson <seanjc@google.com> Subject: [PATCH] x86/sgx: Provide indication of life-cycle of EPC pages
SGX EPC pages go through the following life cycle:
DIRTY ---> FREE ---> IN-USE --\ ^ | \-----------------/
Recovery action for poison for a DIRTY or FREE page is simple. Just make sure never to allocate the page. IN-USE pages need some extra handling.
It would be good to use the sgx_epc_page->owner field as an indicator of where an EPC page is currently in that cycle (owner != NULL means the EPC page is IN-USE). But there is one caller, sgx_alloc_va_page(), that calls with NULL.
Fix up the one holdout to provide a non-NULL owner.
Also change the type of "owner" to "void *" (since it can have other types besides "struct sgx_encl_page *").
Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Tony Luck <tony.luck@intel.com> --- arch/x86/kernel/cpu/sgx/encl.c | 5 +++-- arch/x86/kernel/cpu/sgx/encl.h | 2 +- arch/x86/kernel/cpu/sgx/ioctl.c | 2 +- arch/x86/kernel/cpu/sgx/sgx.h | 2 +- 4 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index 001808e3901c..ad8c61933b0a 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -667,6 +667,7 @@ int sgx_encl_test_and_clear_young(struct mm_struct *mm, /** * sgx_alloc_va_page() - Allocate a Version Array (VA) page + * @va_page: struct sgx_va_page connected to this VA page * * Allocate a free EPC page and convert it to a Version Array (VA) page. * @@ -674,12 +675,12 @@ int sgx_encl_test_and_clear_young(struct mm_struct *mm, * a VA page, * -errno otherwise */ -struct sgx_epc_page *sgx_alloc_va_page(void) +struct sgx_epc_page *sgx_alloc_va_page(struct sgx_va_page *va_page) { struct sgx_epc_page *epc_page; int ret; - epc_page = sgx_alloc_epc_page(NULL, true); + epc_page = sgx_alloc_epc_page(va_page, true); if (IS_ERR(epc_page)) return ERR_CAST(epc_page); diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h index fec43ca65065..3d12dbeae14a 100644 --- a/arch/x86/kernel/cpu/sgx/encl.h +++ b/arch/x86/kernel/cpu/sgx/encl.h @@ -111,7 +111,7 @@ void sgx_encl_put_backing(struct sgx_backing *backing, bool do_write); int sgx_encl_test_and_clear_young(struct mm_struct *mm, struct sgx_encl_page *page); -struct sgx_epc_page *sgx_alloc_va_page(void); +struct sgx_epc_page *sgx_alloc_va_page(struct sgx_va_page *va_page); unsigned int sgx_alloc_va_slot(struct sgx_va_page *va_page); void sgx_free_va_slot(struct sgx_va_page *va_page, unsigned int offset); bool sgx_va_page_full(struct sgx_va_page *va_page); diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c index 83df20e3e633..655ce0bb069d 100644 --- a/arch/x86/kernel/cpu/sgx/ioctl.c +++ b/arch/x86/kernel/cpu/sgx/ioctl.c @@ -30,7 +30,7 @@ static struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl) if (!va_page) return ERR_PTR(-ENOMEM); - va_page->epc_page = sgx_alloc_va_page(); + va_page->epc_page = sgx_alloc_va_page(va_page); if (IS_ERR(va_page->epc_page)) { err = ERR_CAST(va_page->epc_page); kfree(va_page); diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h index 4628acec0009..4e1a410b8a62 100644 --- a/arch/x86/kernel/cpu/sgx/sgx.h +++ b/arch/x86/kernel/cpu/sgx/sgx.h @@ -29,7 +29,7 @@ struct sgx_epc_page { unsigned int section; unsigned int flags; - struct sgx_encl_page *owner; + void *owner; struct list_head list; }; -- 2.29.2
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