]> git.karo-electronics.de Git - linux-beck.git/blobdiff - arch/s390/kvm/kvm-s390.c
KVM: s390: fix memory overwrites when vx is disabled
[linux-beck.git] / arch / s390 / kvm / kvm-s390.c
index 797dbc4e11c3a0cbe309d3a66f6b6325098385b4..4af21c771f9b3925bf860d0dc86cebcc803cf965 100644 (file)
@@ -1244,7 +1244,6 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 
        if (vcpu->kvm->arch.use_cmma)
                kvm_s390_vcpu_unsetup_cmma(vcpu);
-       kfree(vcpu->arch.guest_fpregs.fprs);
        free_page((unsigned long)(vcpu->arch.sie_block));
 
        kvm_vcpu_uninit(vcpu);
@@ -1424,44 +1423,18 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
        return 0;
 }
 
-/*
- * Backs up the current FP/VX register save area on a particular
- * destination.  Used to switch between different register save
- * areas.
- */
-static inline void save_fpu_to(struct fpu *dst)
-{
-       dst->fpc = current->thread.fpu.fpc;
-       dst->regs = current->thread.fpu.regs;
-}
-
-/*
- * Switches the FP/VX register save area from which to lazy
- * restore register contents.
- */
-static inline void load_fpu_from(struct fpu *from)
-{
-       current->thread.fpu.fpc = from->fpc;
-       current->thread.fpu.regs = from->regs;
-}
-
 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 {
        /* Save host register state */
        save_fpu_regs();
-       save_fpu_to(&vcpu->arch.host_fpregs);
-
-       if (test_kvm_facility(vcpu->kvm, 129)) {
-               current->thread.fpu.fpc = vcpu->run->s.regs.fpc;
-               /*
-                * Use the register save area in the SIE-control block
-                * for register restore and save in kvm_arch_vcpu_put()
-                */
-               current->thread.fpu.vxrs =
-                       (__vector128 *)&vcpu->run->s.regs.vrs;
-       } else
-               load_fpu_from(&vcpu->arch.guest_fpregs);
+       vcpu->arch.host_fpregs.fpc = current->thread.fpu.fpc;
+       vcpu->arch.host_fpregs.regs = current->thread.fpu.regs;
 
+       /* Depending on MACHINE_HAS_VX, data stored to vrs either
+        * has vector register or floating point register format.
+        */
+       current->thread.fpu.regs = vcpu->run->s.regs.vrs;
+       current->thread.fpu.fpc = vcpu->run->s.regs.fpc;
        if (test_fp_ctl(current->thread.fpu.fpc))
                /* User space provided an invalid FPC, let's clear it */
                current->thread.fpu.fpc = 0;
@@ -1477,19 +1450,13 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
        atomic_andnot(CPUSTAT_RUNNING, &vcpu->arch.sie_block->cpuflags);
        gmap_disable(vcpu->arch.gmap);
 
+       /* Save guest register state */
        save_fpu_regs();
+       vcpu->run->s.regs.fpc = current->thread.fpu.fpc;
 
-       if (test_kvm_facility(vcpu->kvm, 129))
-               /*
-                * kvm_arch_vcpu_load() set up the register save area to
-                * the &vcpu->run->s.regs.vrs and, thus, the vector registers
-                * are already saved.  Only the floating-point control must be
-                * copied.
-                */
-               vcpu->run->s.regs.fpc = current->thread.fpu.fpc;
-       else
-               save_fpu_to(&vcpu->arch.guest_fpregs);
-       load_fpu_from(&vcpu->arch.host_fpregs);
+       /* Restore host register state */
+       current->thread.fpu.fpc = vcpu->arch.host_fpregs.fpc;
+       current->thread.fpu.regs = vcpu->arch.host_fpregs.regs;
 
        save_access_regs(vcpu->run->s.regs.acrs);
        restore_access_regs(vcpu->arch.host_acrs);
@@ -1507,8 +1474,9 @@ static void kvm_s390_vcpu_initial_reset(struct kvm_vcpu *vcpu)
        memset(vcpu->arch.sie_block->gcr, 0, 16 * sizeof(__u64));
        vcpu->arch.sie_block->gcr[0]  = 0xE0UL;
        vcpu->arch.sie_block->gcr[14] = 0xC2000000UL;
-       vcpu->arch.guest_fpregs.fpc = 0;
-       asm volatile("lfpc %0" : : "Q" (vcpu->arch.guest_fpregs.fpc));
+       /* make sure the new fpc will be lazily loaded */
+       save_fpu_regs();
+       current->thread.fpu.fpc = 0;
        vcpu->arch.sie_block->gbea = 1;
        vcpu->arch.sie_block->pp = 0;
        vcpu->arch.pfault_token = KVM_S390_PFAULT_TOKEN_INVALID;
@@ -1649,27 +1617,14 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,
        vcpu->arch.local_int.wq = &vcpu->wq;
        vcpu->arch.local_int.cpuflags = &vcpu->arch.sie_block->cpuflags;
 
-       /*
-        * Allocate a save area for floating-point registers.  If the vector
-        * extension is available, register contents are saved in the SIE
-        * control block.  The allocated save area is still required in
-        * particular places, for example, in kvm_s390_vcpu_store_status().
-        */
-       vcpu->arch.guest_fpregs.fprs = kzalloc(sizeof(freg_t) * __NUM_FPRS,
-                                              GFP_KERNEL);
-       if (!vcpu->arch.guest_fpregs.fprs)
-               goto out_free_sie_block;
-
        rc = kvm_vcpu_init(vcpu, kvm, id);
        if (rc)
-               goto out_free_fprs;
+               goto out_free_sie_block;
        VM_EVENT(kvm, 3, "create cpu %d at 0x%pK, sie block at 0x%pK", id, vcpu,
                 vcpu->arch.sie_block);
        trace_kvm_s390_create_vcpu(id, vcpu, vcpu->arch.sie_block);
 
        return vcpu;
-out_free_fprs:
-       kfree(vcpu->arch.guest_fpregs.fprs);
 out_free_sie_block:
        free_page((unsigned long)(vcpu->arch.sie_block));
 out_free_cpu:
@@ -1882,19 +1837,27 @@ int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
 
 int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
 {
+       /* make sure the new values will be lazily loaded */
+       save_fpu_regs();
        if (test_fp_ctl(fpu->fpc))
                return -EINVAL;
-       memcpy(vcpu->arch.guest_fpregs.fprs, &fpu->fprs, sizeof(fpu->fprs));
-       vcpu->arch.guest_fpregs.fpc = fpu->fpc;
-       save_fpu_regs();
-       load_fpu_from(&vcpu->arch.guest_fpregs);
+       current->thread.fpu.fpc = fpu->fpc;
+       if (MACHINE_HAS_VX)
+               convert_fp_to_vx(current->thread.fpu.vxrs, (freg_t *)fpu->fprs);
+       else
+               memcpy(current->thread.fpu.fprs, &fpu->fprs, sizeof(fpu->fprs));
        return 0;
 }
 
 int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
 {
-       memcpy(&fpu->fprs, vcpu->arch.guest_fpregs.fprs, sizeof(fpu->fprs));
-       fpu->fpc = vcpu->arch.guest_fpregs.fpc;
+       /* make sure we have the latest values */
+       save_fpu_regs();
+       if (MACHINE_HAS_VX)
+               convert_vx_to_fp((freg_t *)fpu->fprs, current->thread.fpu.vxrs);
+       else
+               memcpy(fpu->fprs, current->thread.fpu.fprs, sizeof(fpu->fprs));
+       fpu->fpc = current->thread.fpu.fpc;
        return 0;
 }
 
@@ -2399,6 +2362,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 int kvm_s390_store_status_unloaded(struct kvm_vcpu *vcpu, unsigned long gpa)
 {
        unsigned char archmode = 1;
+       freg_t fprs[NUM_FPRS];
        unsigned int px;
        u64 clkcomp;
        int rc;
@@ -2414,8 +2378,16 @@ int kvm_s390_store_status_unloaded(struct kvm_vcpu *vcpu, unsigned long gpa)
                gpa = px;
        } else
                gpa -= __LC_FPREGS_SAVE_AREA;
-       rc = write_guest_abs(vcpu, gpa + __LC_FPREGS_SAVE_AREA,
-                            vcpu->arch.guest_fpregs.fprs, 128);
+
+       /* manually convert vector registers if necessary */
+       if (MACHINE_HAS_VX) {
+               convert_vx_to_fp(fprs, current->thread.fpu.vxrs);
+               rc = write_guest_abs(vcpu, gpa + __LC_FPREGS_SAVE_AREA,
+                                    fprs, 128);
+       } else {
+               rc = write_guest_abs(vcpu, gpa + __LC_FPREGS_SAVE_AREA,
+                                    vcpu->run->s.regs.vrs, 128);
+       }
        rc |= write_guest_abs(vcpu, gpa + __LC_GPREGS_SAVE_AREA,
                              vcpu->run->s.regs.gprs, 128);
        rc |= write_guest_abs(vcpu, gpa + __LC_PSW_SAVE_AREA,
@@ -2423,7 +2395,7 @@ int kvm_s390_store_status_unloaded(struct kvm_vcpu *vcpu, unsigned long gpa)
        rc |= write_guest_abs(vcpu, gpa + __LC_PREFIX_SAVE_AREA,
                              &px, 4);
        rc |= write_guest_abs(vcpu, gpa + __LC_FP_CREG_SAVE_AREA,
-                             &vcpu->arch.guest_fpregs.fpc, 4);
+                             &vcpu->run->s.regs.fpc, 4);
        rc |= write_guest_abs(vcpu, gpa + __LC_TOD_PROGREG_SAVE_AREA,
                              &vcpu->arch.sie_block->todpr, 4);
        rc |= write_guest_abs(vcpu, gpa + __LC_CPU_TIMER_SAVE_AREA,
@@ -2446,19 +2418,7 @@ int kvm_s390_vcpu_store_status(struct kvm_vcpu *vcpu, unsigned long addr)
         * it into the save area
         */
        save_fpu_regs();
-       if (test_kvm_facility(vcpu->kvm, 129)) {
-               /*
-                * If the vector extension is available, the vector registers
-                * which overlaps with floating-point registers are saved in
-                * the SIE-control block.  Hence, extract the floating-point
-                * registers and the FPC value and store them in the
-                * guest_fpregs structure.
-                */
-               vcpu->arch.guest_fpregs.fpc = current->thread.fpu.fpc;
-               convert_vx_to_fp(vcpu->arch.guest_fpregs.fprs,
-                                current->thread.fpu.vxrs);
-       } else
-               save_fpu_to(&vcpu->arch.guest_fpregs);
+       vcpu->run->s.regs.fpc = current->thread.fpu.fpc;
        save_access_regs(vcpu->run->s.regs.acrs);
 
        return kvm_s390_store_status_unloaded(vcpu, addr);