x86/fpu: Replace KVMs xstate component clearing

In order to prepare for the support of dynamically enabled FPU features,
move the clearing of xstate components to the FPU core code.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: kvm@vger.kernel.org
Link: https://lkml.kernel.org/r/20211013145322.399567049@linutronix.de

diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
index 5ac5e4596b536d5ca9ea3473dc41cb6e0c01eb12..a97cf3e5887bdc654e891e95176841511818fa2f 100644 (file)
--- a/arch/x86/include/asm/fpu/api.h
+++ b/arch/x86/include/asm/fpu/api.h
@@ -132,6 +132,7 @@ DECLARE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx);
 
 /* fpstate-related functions which are exported to KVM */
 extern void fpu_init_fpstate_user(struct fpu *fpu);
+extern void fpstate_clear_xstate_component(struct fpstate *fps, unsigned int xfeature);
 
 /* KVM specific functions */
 extern void fpu_swap_kvm_fpu(struct fpu *save, struct fpu *rstor, u64 restore_mask);

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index b8cebc0ee420b4d272a0677bfb784c57baedabf8..fb329bbfe89f219b67703bfc364368b69876a1de 100644 (file)
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -128,7 +128,6 @@ extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
 extern void __init update_regset_xstate_info(unsigned int size,
                                             u64 xstate_mask);
 
-void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr);
 int xfeature_size(int xfeature_nr);
 int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf);
 int copy_sigframe_from_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf);

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 937ad5b394ca1dd2130bc17ea2e7facd12a6ca75..b1409a769ba5800fd56c3af4c015852853b0d8e9 100644 (file)
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -908,7 +908,6 @@ void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr)
 
        return __raw_xsave_addr(xsave, xfeature_nr);
 }
-EXPORT_SYMBOL_GPL(get_xsave_addr);
 
 #ifdef CONFIG_ARCH_HAS_PKEYS
 
@@ -1257,6 +1256,17 @@ void xrstors(struct xregs_state *xstate, u64 mask)
        WARN_ON_ONCE(err);
 }
 
+#if IS_ENABLED(CONFIG_KVM)
+void fpstate_clear_xstate_component(struct fpstate *fps, unsigned int xfeature)
+{
+       void *addr = get_xsave_addr(&fps->regs.xsave, xfeature);
+
+       if (addr)
+               memset(addr, 0, xstate_sizes[xfeature]);
+}
+EXPORT_SYMBOL_GPL(fpstate_clear_xstate_component);
+#endif
+
 #ifdef CONFIG_PROC_PID_ARCH_STATUS
 /*
  * Report the amount of time elapsed in millisecond since last AVX512

diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h
index bb6d7d298d2a9c290d77b2eae0294ef01b166be5..99f8cfec719daede2cb31503b8a27f91cb848142 100644 (file)
--- a/arch/x86/kernel/fpu/xstate.h
+++ b/arch/x86/kernel/fpu/xstate.h
@@ -21,6 +21,8 @@ extern void __copy_xstate_to_uabi_buf(struct membuf to, struct xregs_state *xsav
 extern void fpu__init_cpu_xstate(void);
 extern void fpu__init_system_xstate(void);
 
+extern void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr);
+
 /* XSAVE/XRSTOR wrapper functions */
 
 #ifdef CONFIG_X86_64

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a18d4670e640417be9c18a8cff792ccf685fc111..96936a2e8267709a59010a6d2e3d920edab28e42 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10705,7 +10705,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
        vcpu->arch.apf.halted = false;
 
        if (vcpu->arch.guest_fpu && kvm_mpx_supported()) {
-               void *mpx_state_buffer;
+               struct fpstate *fpstate = vcpu->arch.guest_fpu->fpstate;
 
                /*
                 * To avoid have the INIT path from kvm_apic_has_events() that be
@@ -10713,14 +10713,10 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
                 */
                if (init_event)
                        kvm_put_guest_fpu(vcpu);
-               mpx_state_buffer = get_xsave_addr(&vcpu->arch.guest_fpu->state.xsave,
-                                       XFEATURE_BNDREGS);
-               if (mpx_state_buffer)
-                       memset(mpx_state_buffer, 0, sizeof(struct mpx_bndreg_state));
-               mpx_state_buffer = get_xsave_addr(&vcpu->arch.guest_fpu->state.xsave,
-                                       XFEATURE_BNDCSR);
-               if (mpx_state_buffer)
-                       memset(mpx_state_buffer, 0, sizeof(struct mpx_bndcsr));
+
+               fpstate_clear_xstate_component(fpstate, XFEATURE_BNDREGS);
+               fpstate_clear_xstate_component(fpstate, XFEATURE_BNDCSR);
+
                if (init_event)
                        kvm_load_guest_fpu(vcpu);
        }