| Message ID | 20240507235344.249103-3-chang.seok.bae@intel.com (mailing list archive) |
|---|---|
| State | Changes Requested, archived |
| Headers | show |
| Series | x86/fpu: Extend kernel_fpu_begin_mask() for the In-Field Scan driver | expand |
On Tue, May 07, 2024 at 04:53:44PM -0700, Bae, Chang Seok wrote: > In-Field Scan aborts if AMX state is not in initialized state. Use > kernel_fpu_begin_mask(KFPU_AMX) to ensure AMX state is initialized. > > Introduce custom FPU handling wrappers to ensure compliance with the > established FPU API semantics. This change follows the EFI case from > commit b0dc553cfc9d ("x86/fpu: Make the EFI FPU calling convention > explicit"). > > Then, use these wrappers to surround the MSR_ACTIVATE_SCAN write to > minimize the critical section. To prevent unnecessary delays, invoke > ifs_fpu_begin() before entering the rendezvous loop. > > Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> > Reviewed-by: Jithu Joseph <jithu.joseph@intel.com> > Tested-by: Jithu Joseph <jithu.joseph@intel.com> > Acked-by: Hans de Goede <hdegoede@redhat.com> Reviewed-by: Ashok Raj <ashok.raj@intel.com> for both patches.
On 5/7/2024 5:19 PM, Ashok Raj wrote: > > Reviewed-by: Ashok Raj <ashok.raj@intel.com> > > for both patches. Thanks!
diff --git a/drivers/platform/x86/intel/ifs/ifs.h b/drivers/platform/x86/intel/ifs/ifs.h index 56b9f3e3cf76..a2ec0dab809b 100644 --- a/drivers/platform/x86/intel/ifs/ifs.h +++ b/drivers/platform/x86/intel/ifs/ifs.h @@ -129,6 +129,7 @@ */ #include <linux/device.h> #include <linux/miscdevice.h> +#include <asm/fpu/api.h> #define MSR_ARRAY_BIST 0x00000105 #define MSR_COPY_SCAN_HASHES 0x000002c2 @@ -325,4 +326,18 @@ int do_core_test(int cpu, struct device *dev); extern struct attribute *plat_ifs_attrs[]; extern struct attribute *plat_ifs_array_attrs[]; +static inline void ifs_fpu_begin(void) +{ + /* + * The AMX state must be initialized prior to executing In-Field + * Scan tests, according to Intel SDM. + */ + kernel_fpu_begin_mask(KFPU_AMX); +} + +static inline void ifs_fpu_end(void) +{ + kernel_fpu_end(); +} + #endif diff --git a/drivers/platform/x86/intel/ifs/runtest.c b/drivers/platform/x86/intel/ifs/runtest.c index 95b4b71fab53..ca2b496a6b01 100644 --- a/drivers/platform/x86/intel/ifs/runtest.c +++ b/drivers/platform/x86/intel/ifs/runtest.c @@ -188,6 +188,9 @@ static int doscan(void *data) /* Only the first logical CPU on a core reports result */ first = cpumask_first(cpu_smt_mask(cpu)); + /* Prepare FPU state before entering the rendezvous loop */ + ifs_fpu_begin(); + wait_for_sibling_cpu(&scan_cpus_in, NSEC_PER_SEC); /* @@ -199,6 +202,9 @@ static int doscan(void *data) * are processed in a single pass) before it retires. */ wrmsrl(MSR_ACTIVATE_SCAN, params->activate->data); + + ifs_fpu_end(); + rdmsrl(MSR_SCAN_STATUS, status.data); trace_ifs_status(ifsd->cur_batch, start, stop, status.data);
In-Field Scan aborts if AMX state is not in initialized state. Use kernel_fpu_begin_mask(KFPU_AMX) to ensure AMX state is initialized. Introduce custom FPU handling wrappers to ensure compliance with the established FPU API semantics. This change follows the EFI case from commit b0dc553cfc9d ("x86/fpu: Make the EFI FPU calling convention explicit"). Then, use these wrappers to surround the MSR_ACTIVATE_SCAN write to minimize the critical section. To prevent unnecessary delays, invoke ifs_fpu_begin() before entering the rendezvous loop. Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> Reviewed-by: Jithu Joseph <jithu.joseph@intel.com> Tested-by: Jithu Joseph <jithu.joseph@intel.com> Acked-by: Hans de Goede <hdegoede@redhat.com> --- V1 -> V2: Massage the changelog (Ashok), add a space to the code comment (Ilpo), and include the header file explicitly (0-day). --- drivers/platform/x86/intel/ifs/ifs.h | 15 +++++++++++++++ drivers/platform/x86/intel/ifs/runtest.c | 6 ++++++ 2 files changed, 21 insertions(+)