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Date: Wed, 22 Sep 2021 16:30:43 -0700 From: Reinette Chatre <reinette.chatre@...el.com> To: Jarkko Sakkinen <jarkko@...nel.org>, Dave Hansen <dave.hansen@...ux.intel.com>, Thomas Gleixner <tglx@...utronix.de>, "Ingo Molnar" <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, <x86@...nel.org>, "H. Peter Anvin" <hpa@...or.com>, Jonathan Corbet <corbet@....net> CC: <linux-sgx@...r.kernel.org>, <linux-kernel@...r.kernel.org>, <linux-doc@...r.kernel.org> Subject: Re: [PATCH v5 2/2] x86/sgx: Add an attribute for the amount of SGX memory in a NUMA node Hi Jarkko, On 9/13/2021 8:04 PM, Jarkko Sakkinen wrote: > The amount of SGX memory on the system is determined by the BIOS and it > varies wildly between systems. It can be from dozens of MB's on desktops > or VM's, up to many GB's on servers. Just like for regular memory, it is > sometimes useful to know the amount of usable SGX memory in the system. > > Add an attribute for the amount of SGX memory in bytes to each NUMA > node. The path is /sys/devices/system/node/node[0-9]*/sgx/memory_size. > > Signed-off-by: Jarkko Sakkinen <jarkko@...nel.org> > > --- > v5: A new patch based on the discussion at > https://lore.kernel.org/linux-sgx/3a7cab4115b4f902f3509ad8652e616b91703e1d.camel@kernel.org/T/#t > --- > Documentation/x86/sgx.rst | 14 ++++++ > arch/x86/kernel/cpu/sgx/main.c | 90 ++++++++++++++++++++++++++++++++++ > arch/x86/kernel/cpu/sgx/sgx.h | 2 + > 3 files changed, 106 insertions(+) > ... > diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c > index a6e313f1a82d..c43b5a0120c1 100644 > --- a/arch/x86/kernel/cpu/sgx/main.c > +++ b/arch/x86/kernel/cpu/sgx/main.c > @@ -717,6 +717,7 @@ static bool __init sgx_page_cache_init(void) > } > > sgx_epc_sections[i].node = &sgx_numa_nodes[nid]; > + sgx_numa_nodes[nid].size += size; > > sgx_nr_epc_sections++; > } The above memory seems to be uninitialized at the time it is incremented. I tried this out on a system that reports the following: $ dmesg | grep EPC [ 7.252838] sgx: EPC section 0x1000c00000-0x107f7fffff [ 7.256921] sgx: EPC section 0x2000c00000-0x207fffffff It shows unexpectedly large values: $ cat /sys/devices/system/node/node*/sgx/memory_size 12421486739271732874 16308428754864105707 System reported sane values after adding this fixup: diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 3380390cc052..d73bbfbfc05d 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -621,7 +621,7 @@ static bool __init sgx_page_cache_init(void) int nid; int i; - sgx_numa_nodes = kmalloc_array(num_possible_nodes(), sizeof(*sgx_numa_nodes), GFP_KERNEL); + sgx_numa_nodes = kcalloc(num_possible_nodes(), sizeof(*sgx_numa_nodes), GFP_KERNEL); if (!sgx_numa_nodes) return false; After fixup: $ cat /sys/devices/system/node/node*/sgx/memory_size 2126512128 2134900736 Reinette
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