| Message ID | 20210927213452.212470-3-tony.luck@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Basic recovery for machine checks inside SGX | expand |
On Mon, 2021-09-27 at 14:34 -0700, Tony Luck wrote: > X86 machine check architecture reports a physical address when there > is a memory error. Handling that error requires a method to determine > whether the physical address reported is in any of the areas reserved > for EPC pages by BIOS. > > SGX EPC pages do not have Linux "struct page" associated with them. > > Keep track of the mapping from ranges of EPC pages to the sections > that contain them using an xarray. > > Create a function arch_is_platform_page() that simply reports whether an address > is an EPC page for use elsewhere in the kernel. The ACPI error injection > code needs this function and is typically built as a module, so export it. > > Note that arch_is_platform_page() will be slower than other similar "what type > is this page" functions that can simply check bits in the "struct page". > If there is some future performance critical user of this function it > may need to be implemented in a more efficient way. > > Note also that the current implementation of xarray allocates a few > hundred kilobytes for this usage on a system with 4GB of SGX EPC memory > configured. This isn't ideal, but worth it for the code simplicity. > > Signed-off-by: Tony Luck <tony.luck@intel.com> > --- > arch/x86/kernel/cpu/sgx/main.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c > index d18988a46c13..09fa42690ff2 100644 > --- a/arch/x86/kernel/cpu/sgx/main.c > +++ b/arch/x86/kernel/cpu/sgx/main.c > @@ -20,6 +20,7 @@ struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS]; > static int sgx_nr_epc_sections; > static struct task_struct *ksgxd_tsk; > static DECLARE_WAIT_QUEUE_HEAD(ksgxd_waitq); > +static DEFINE_XARRAY(sgx_epc_address_space); > > /* > * These variables are part of the state of the reclaimer, and must be accessed > @@ -650,6 +651,8 @@ static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size, > } > > section->phys_addr = phys_addr; > + xa_store_range(&sgx_epc_address_space, section->phys_addr, > + phys_addr + size - 1, section, GFP_KERNEL); > > for (i = 0; i < nr_pages; i++) { > section->pages[i].section = index; > @@ -661,6 +664,12 @@ static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size, > return true; > } > > +bool arch_is_platform_page(u64 paddr) > +{ > + return !!xa_load(&sgx_epc_address_space, paddr); > +} > +EXPORT_SYMBOL_GPL(arch_is_platform_page); > + > /** > * A section metric is concatenated in a way that @low bits 12-31 define the > * bits 12-31 of the metric and @high bits 0-19 define the bits 32-51 of the Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> /Jarkko
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index d18988a46c13..09fa42690ff2 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -20,6 +20,7 @@ struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS]; static int sgx_nr_epc_sections; static struct task_struct *ksgxd_tsk; static DECLARE_WAIT_QUEUE_HEAD(ksgxd_waitq); +static DEFINE_XARRAY(sgx_epc_address_space); /* * These variables are part of the state of the reclaimer, and must be accessed @@ -650,6 +651,8 @@ static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size, } section->phys_addr = phys_addr; + xa_store_range(&sgx_epc_address_space, section->phys_addr, + phys_addr + size - 1, section, GFP_KERNEL); for (i = 0; i < nr_pages; i++) { section->pages[i].section = index; @@ -661,6 +664,12 @@ static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size, return true; } +bool arch_is_platform_page(u64 paddr) +{ + return !!xa_load(&sgx_epc_address_space, paddr); +} +EXPORT_SYMBOL_GPL(arch_is_platform_page); + /** * A section metric is concatenated in a way that @low bits 12-31 define the * bits 12-31 of the metric and @high bits 0-19 define the bits 32-51 of the
X86 machine check architecture reports a physical address when there is a memory error. Handling that error requires a method to determine whether the physical address reported is in any of the areas reserved for EPC pages by BIOS. SGX EPC pages do not have Linux "struct page" associated with them. Keep track of the mapping from ranges of EPC pages to the sections that contain them using an xarray. Create a function arch_is_platform_page() that simply reports whether an address is an EPC page for use elsewhere in the kernel. The ACPI error injection code needs this function and is typically built as a module, so export it. Note that arch_is_platform_page() will be slower than other similar "what type is this page" functions that can simply check bits in the "struct page". If there is some future performance critical user of this function it may need to be implemented in a more efficient way. Note also that the current implementation of xarray allocates a few hundred kilobytes for this usage on a system with 4GB of SGX EPC memory configured. This isn't ideal, but worth it for the code simplicity. Signed-off-by: Tony Luck <tony.luck@intel.com> --- arch/x86/kernel/cpu/sgx/main.c | 9 +++++++++ 1 file changed, 9 insertions(+)