[Xen-devel] [PATCH 0 of 8] FPU LWP: patch description

["Huang2, Wei" <Wei.Huang2@xxxxxxx>]

This patch set supports AMD lightweight profiling for SVM guests. Because LWP 
isn't tracked by CR0.TS bit, we clean up the FPU code to handle lazy and unlazy 
FPU states differently. Lazy FPU state (such as SSE, YMM) is handled when #NM 
is triggered. Unlazy state, such as LWP, is saved and restored on each vcpu 
context switch.

Per Keir's comments, I moved extended state related code into xstate.c and 
xstate.h. The FPU related code in i387.c was also cleaned up and has consistent 
names now. The comments from Jan Beulich were also taken. I added a new 
variable, nonlazy_xstate_used, to control whether save/restore nonlazy state.

====== i387.c ======
* void vcpu_restore_fpu_eager(struct vcpu *v);
* void vcpu_restore_fpu_lazy(struct vcpu *v);
* void vcpu_save_fpu(struct vcpu *v);
* int vcpu_init_fpu(struct vcpu *v);
* void vcpu_destroy_fpu(struct vcpu *v);

====== xstate.c ======
* void set_xcr0(u64 xfeatures);
* uint64_t get_xcr0(void);
* void xsave(struct vcpu *v, uint64_t mask);
* void xrstor(struct vcpu *v, uint64_t mask);
* bool_t xsave_enabled(const struct vcpu *v);
* void xstate_free_save_area(struct vcpu *v);
* int xstate_alloc_save_area(struct vcpu *v);
* void xstate_init(void);


This code has been tested on real hardware. Please comment.

-Wei


 b/xen/arch/x86/xstate.c            |  188 +++++++++++++++
 b/xen/include/asm-x86/xstate.h     |   72 +++++
 tools/libxc/xc_cpuid_x86.c         |    6
 xen/arch/x86/Makefile              |    1
 xen/arch/x86/acpi/suspend.c        |    2
 xen/arch/x86/cpu/common.c          |    4
 xen/arch/x86/domain.c              |   29 --
 xen/arch/x86/domctl.c              |    2
 xen/arch/x86/hvm/hvm.c             |    3
 xen/arch/x86/hvm/svm/svm.c         |   75 ++++++
 xen/arch/x86/hvm/svm/vmcb.c        |    5
 xen/arch/x86/hvm/vmx/vmcs.c        |    1
 xen/arch/x86/hvm/vmx/vmx.c         |    2
 xen/arch/x86/i387.c                |  450 ++++++++++++++++---------------------
 xen/arch/x86/traps.c               |    3
 xen/include/asm-x86/cpufeature.h   |    2
 xen/include/asm-x86/domain.h       |    5
 xen/include/asm-x86/hvm/svm/vmcb.h |    3
 xen/include/asm-x86/i387.h         |   71 -----
 xen/include/asm-x86/msr-index.h    |    4
 20 files changed, 573 insertions(+), 355 deletions(-)


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