nested SVM: adjust guest handling of structure mappings For one, nestedsvm_vmcb_map() error checking must not consist of using assertions: Global (permanent) mappings can fail, and hence failure needs to be dealt with properly. And non-global (transient) mappings can't fail anyway. And then the I/O port access bitmap handling was broken: It checked only to first of the accessed ports rather than each of them. Signed-off-by: Jan Beulich --- v2: Refine the change to nsvm_vmrun_permissionmap() - hvm_map_guest_frame_*() can return NULL for reasons other than map_domain_page_global() doing so (pointed out by Andrew Cooper). That leaves the function broken though (it ought to handle the shared/paged out cases in an appropriate way). --- a/xen/arch/x86/hvm/svm/nestedsvm.c +++ b/xen/arch/x86/hvm/svm/nestedsvm.c @@ -342,7 +342,7 @@ static int nsvm_vmrun_permissionmap(stru unsigned int i; enum hvm_copy_result ret; unsigned long *ns_viomap; - bool_t ioport_80, ioport_ed; + bool_t ioport_80 = 1, ioport_ed = 1; ns_msrpm_ptr = (unsigned long *)svm->ns_cached_msrpm; @@ -360,10 +360,12 @@ static int nsvm_vmrun_permissionmap(stru svm->ns_iomap_pa = ns_vmcb->_iopm_base_pa; ns_viomap = hvm_map_guest_frame_ro(svm->ns_iomap_pa >> PAGE_SHIFT, 0); - ASSERT(ns_viomap != NULL); - ioport_80 = test_bit(0x80, ns_viomap); - ioport_ed = test_bit(0xed, ns_viomap); - hvm_unmap_guest_frame(ns_viomap, 0); + if ( ns_viomap ) + { + ioport_80 = test_bit(0x80, ns_viomap); + ioport_ed = test_bit(0xed, ns_viomap); + hvm_unmap_guest_frame(ns_viomap, 0); + } svm->ns_iomap = nestedhvm_vcpu_iomap_get(ioport_80, ioport_ed); @@ -866,40 +868,45 @@ nsvm_vmcb_guest_intercepts_msr(unsigned static int nsvm_vmcb_guest_intercepts_ioio(paddr_t iopm_pa, uint64_t exitinfo1) { - unsigned long iopm_gfn = iopm_pa >> PAGE_SHIFT; - unsigned long *io_bitmap = NULL; + unsigned long gfn = iopm_pa >> PAGE_SHIFT; + unsigned long *io_bitmap; ioio_info_t ioinfo; uint16_t port; + unsigned int size; bool_t enabled; - unsigned long gfn = 0; /* gcc ... */ ioinfo.bytes = exitinfo1; port = ioinfo.fields.port; + size = ioinfo.fields.sz32 ? 4 : ioinfo.fields.sz16 ? 2 : 1; - switch (port) { - case 0 ... 32767: /* first 4KB page */ - gfn = iopm_gfn; + switch ( port ) + { + case 0 ... 8 * PAGE_SIZE - 1: /* first 4KB page */ break; - case 32768 ... 65535: /* second 4KB page */ - port -= 32768; - gfn = iopm_gfn + 1; + case 8 * PAGE_SIZE ... 2 * 8 * PAGE_SIZE - 1: /* second 4KB page */ + port -= 8 * PAGE_SIZE; + ++gfn; break; default: BUG(); break; } - io_bitmap = hvm_map_guest_frame_ro(gfn, 0); - if (io_bitmap == NULL) { - gdprintk(XENLOG_ERR, - "IOIO intercept: mapping of permission map failed\n"); - return NESTEDHVM_VMEXIT_ERROR; + for ( io_bitmap = hvm_map_guest_frame_ro(gfn, 0); ; ) + { + enabled = test_bit(port, io_bitmap); + if ( !enabled || !--size ) + break; + if ( unlikely(++port == 8 * PAGE_SIZE) ) + { + hvm_unmap_guest_frame(io_bitmap, 0); + io_bitmap = hvm_map_guest_frame_ro(++gfn, 0); + port -= 8 * PAGE_SIZE; + } } - - enabled = test_bit(port, io_bitmap); hvm_unmap_guest_frame(io_bitmap, 0); - if (!enabled) + if ( !enabled ) return NESTEDHVM_VMEXIT_HOST; return NESTEDHVM_VMEXIT_INJECT; @@ -966,8 +973,8 @@ nsvm_vmcb_guest_intercepts_exitcode(stru switch (exitcode) { case VMEXIT_MSR: ASSERT(regs != NULL); - nestedsvm_vmcb_map(v, nv->nv_vvmcxaddr); - ASSERT(nv->nv_vvmcx != NULL); + if ( !nestedsvm_vmcb_map(v, nv->nv_vvmcxaddr) ) + break; ns_vmcb = nv->nv_vvmcx; vmexits = nsvm_vmcb_guest_intercepts_msr(svm->ns_cached_msrpm, regs->ecx, ns_vmcb->exitinfo1 != 0); @@ -975,8 +982,8 @@ nsvm_vmcb_guest_intercepts_exitcode(stru return 0; break; case VMEXIT_IOIO: - nestedsvm_vmcb_map(v, nv->nv_vvmcxaddr); - ASSERT(nv->nv_vvmcx != NULL); + if ( !nestedsvm_vmcb_map(v, nv->nv_vvmcxaddr) ) + break; ns_vmcb = nv->nv_vvmcx; vmexits = nsvm_vmcb_guest_intercepts_ioio(ns_vmcb->_iopm_base_pa, ns_vmcb->exitinfo1);