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-rw-r--r--arch/s390/kvm/gaccess.c536
1 files changed, 536 insertions, 0 deletions
diff --git a/arch/s390/kvm/gaccess.c b/arch/s390/kvm/gaccess.c
new file mode 100644
index 000000000000..916e1ee1f8c9
--- /dev/null
+++ b/arch/s390/kvm/gaccess.c
@@ -0,0 +1,536 @@
+/*
+ * guest access functions
+ *
+ * Copyright IBM Corp. 2014
+ *
+ */
+
+#include <linux/vmalloc.h>
+#include <linux/err.h>
+#include <asm/pgtable.h>
+#include "kvm-s390.h"
+#include "gaccess.h"
+
+union asce {
+ unsigned long val;
+ struct {
+ unsigned long origin : 52; /* Region- or Segment-Table Origin */
+ unsigned long : 2;
+ unsigned long g : 1; /* Subspace Group Control */
+ unsigned long p : 1; /* Private Space Control */
+ unsigned long s : 1; /* Storage-Alteration-Event Control */
+ unsigned long x : 1; /* Space-Switch-Event Control */
+ unsigned long r : 1; /* Real-Space Control */
+ unsigned long : 1;
+ unsigned long dt : 2; /* Designation-Type Control */
+ unsigned long tl : 2; /* Region- or Segment-Table Length */
+ };
+};
+
+enum {
+ ASCE_TYPE_SEGMENT = 0,
+ ASCE_TYPE_REGION3 = 1,
+ ASCE_TYPE_REGION2 = 2,
+ ASCE_TYPE_REGION1 = 3
+};
+
+union region1_table_entry {
+ unsigned long val;
+ struct {
+ unsigned long rto: 52;/* Region-Table Origin */
+ unsigned long : 2;
+ unsigned long p : 1; /* DAT-Protection Bit */
+ unsigned long : 1;
+ unsigned long tf : 2; /* Region-Second-Table Offset */
+ unsigned long i : 1; /* Region-Invalid Bit */
+ unsigned long : 1;
+ unsigned long tt : 2; /* Table-Type Bits */
+ unsigned long tl : 2; /* Region-Second-Table Length */
+ };
+};
+
+union region2_table_entry {
+ unsigned long val;
+ struct {
+ unsigned long rto: 52;/* Region-Table Origin */
+ unsigned long : 2;
+ unsigned long p : 1; /* DAT-Protection Bit */
+ unsigned long : 1;
+ unsigned long tf : 2; /* Region-Third-Table Offset */
+ unsigned long i : 1; /* Region-Invalid Bit */
+ unsigned long : 1;
+ unsigned long tt : 2; /* Table-Type Bits */
+ unsigned long tl : 2; /* Region-Third-Table Length */
+ };
+};
+
+struct region3_table_entry_fc0 {
+ unsigned long sto: 52;/* Segment-Table Origin */
+ unsigned long : 1;
+ unsigned long fc : 1; /* Format-Control */
+ unsigned long p : 1; /* DAT-Protection Bit */
+ unsigned long : 1;
+ unsigned long tf : 2; /* Segment-Table Offset */
+ unsigned long i : 1; /* Region-Invalid Bit */
+ unsigned long cr : 1; /* Common-Region Bit */
+ unsigned long tt : 2; /* Table-Type Bits */
+ unsigned long tl : 2; /* Segment-Table Length */
+};
+
+struct region3_table_entry_fc1 {
+ unsigned long rfaa : 33; /* Region-Frame Absolute Address */
+ unsigned long : 14;
+ unsigned long av : 1; /* ACCF-Validity Control */
+ unsigned long acc: 4; /* Access-Control Bits */
+ unsigned long f : 1; /* Fetch-Protection Bit */
+ unsigned long fc : 1; /* Format-Control */
+ unsigned long p : 1; /* DAT-Protection Bit */
+ unsigned long co : 1; /* Change-Recording Override */
+ unsigned long : 2;
+ unsigned long i : 1; /* Region-Invalid Bit */
+ unsigned long cr : 1; /* Common-Region Bit */
+ unsigned long tt : 2; /* Table-Type Bits */
+ unsigned long : 2;
+};
+
+union region3_table_entry {
+ unsigned long val;
+ struct region3_table_entry_fc0 fc0;
+ struct region3_table_entry_fc1 fc1;
+ struct {
+ unsigned long : 53;
+ unsigned long fc : 1; /* Format-Control */
+ unsigned long : 4;
+ unsigned long i : 1; /* Region-Invalid Bit */
+ unsigned long cr : 1; /* Common-Region Bit */
+ unsigned long tt : 2; /* Table-Type Bits */
+ unsigned long : 2;
+ };
+};
+
+struct segment_entry_fc0 {
+ unsigned long pto: 53;/* Page-Table Origin */
+ unsigned long fc : 1; /* Format-Control */
+ unsigned long p : 1; /* DAT-Protection Bit */
+ unsigned long : 3;
+ unsigned long i : 1; /* Segment-Invalid Bit */
+ unsigned long cs : 1; /* Common-Segment Bit */
+ unsigned long tt : 2; /* Table-Type Bits */
+ unsigned long : 2;
+};
+
+struct segment_entry_fc1 {
+ unsigned long sfaa : 44; /* Segment-Frame Absolute Address */
+ unsigned long : 3;
+ unsigned long av : 1; /* ACCF-Validity Control */
+ unsigned long acc: 4; /* Access-Control Bits */
+ unsigned long f : 1; /* Fetch-Protection Bit */
+ unsigned long fc : 1; /* Format-Control */
+ unsigned long p : 1; /* DAT-Protection Bit */
+ unsigned long co : 1; /* Change-Recording Override */
+ unsigned long : 2;
+ unsigned long i : 1; /* Segment-Invalid Bit */
+ unsigned long cs : 1; /* Common-Segment Bit */
+ unsigned long tt : 2; /* Table-Type Bits */
+ unsigned long : 2;
+};
+
+union segment_table_entry {
+ unsigned long val;
+ struct segment_entry_fc0 fc0;
+ struct segment_entry_fc1 fc1;
+ struct {
+ unsigned long : 53;
+ unsigned long fc : 1; /* Format-Control */
+ unsigned long : 4;
+ unsigned long i : 1; /* Segment-Invalid Bit */
+ unsigned long cs : 1; /* Common-Segment Bit */
+ unsigned long tt : 2; /* Table-Type Bits */
+ unsigned long : 2;
+ };
+};
+
+enum {
+ TABLE_TYPE_SEGMENT = 0,
+ TABLE_TYPE_REGION3 = 1,
+ TABLE_TYPE_REGION2 = 2,
+ TABLE_TYPE_REGION1 = 3
+};
+
+union page_table_entry {
+ unsigned long val;
+ struct {
+ unsigned long pfra : 52; /* Page-Frame Real Address */
+ unsigned long z : 1; /* Zero Bit */
+ unsigned long i : 1; /* Page-Invalid Bit */
+ unsigned long p : 1; /* DAT-Protection Bit */
+ unsigned long co : 1; /* Change-Recording Override */
+ unsigned long : 8;
+ };
+};
+
+/*
+ * vaddress union in order to easily decode a virtual address into its
+ * region first index, region second index etc. parts.
+ */
+union vaddress {
+ unsigned long addr;
+ struct {
+ unsigned long rfx : 11;
+ unsigned long rsx : 11;
+ unsigned long rtx : 11;
+ unsigned long sx : 11;
+ unsigned long px : 8;
+ unsigned long bx : 12;
+ };
+ struct {
+ unsigned long rfx01 : 2;
+ unsigned long : 9;
+ unsigned long rsx01 : 2;
+ unsigned long : 9;
+ unsigned long rtx01 : 2;
+ unsigned long : 9;
+ unsigned long sx01 : 2;
+ unsigned long : 29;
+ };
+};
+
+/*
+ * raddress union which will contain the result (real or absolute address)
+ * after a page table walk. The rfaa, sfaa and pfra members are used to
+ * simply assign them the value of a region, segment or page table entry.
+ */
+union raddress {
+ unsigned long addr;
+ unsigned long rfaa : 33; /* Region-Frame Absolute Address */
+ unsigned long sfaa : 44; /* Segment-Frame Absolute Address */
+ unsigned long pfra : 52; /* Page-Frame Real Address */
+};
+
+static unsigned long get_vcpu_asce(struct kvm_vcpu *vcpu)
+{
+ switch (psw_bits(vcpu->arch.sie_block->gpsw).as) {
+ case PSW_AS_PRIMARY:
+ return vcpu->arch.sie_block->gcr[1];
+ case PSW_AS_SECONDARY:
+ return vcpu->arch.sie_block->gcr[7];
+ case PSW_AS_HOME:
+ return vcpu->arch.sie_block->gcr[13];
+ }
+ return 0;
+}
+
+static int deref_table(struct kvm *kvm, unsigned long gpa, unsigned long *val)
+{
+ return kvm_read_guest(kvm, gpa, val, sizeof(*val));
+}
+
+/**
+ * guest_translate - translate a guest virtual into a guest absolute address
+ * @vcpu: virtual cpu
+ * @gva: guest virtual address
+ * @gpa: points to where guest physical (absolute) address should be stored
+ * @write: indicates if access is a write access
+ *
+ * Translate a guest virtual address into a guest absolute address by means
+ * of dynamic address translation as specified by the architecuture.
+ * If the resulting absolute address is not available in the configuration
+ * an addressing exception is indicated and @gpa will not be changed.
+ *
+ * Returns: - zero on success; @gpa contains the resulting absolute address
+ * - a negative value if guest access failed due to e.g. broken
+ * guest mapping
+ * - a positve value if an access exception happened. In this case
+ * the returned value is the program interruption code as defined
+ * by the architecture
+ */
+static unsigned long guest_translate(struct kvm_vcpu *vcpu, unsigned long gva,
+ unsigned long *gpa, int write)
+{
+ union vaddress vaddr = {.addr = gva};
+ union raddress raddr = {.addr = gva};
+ union page_table_entry pte;
+ int dat_protection = 0;
+ union ctlreg0 ctlreg0;
+ unsigned long ptr;
+ int edat1, edat2;
+ union asce asce;
+
+ ctlreg0.val = vcpu->arch.sie_block->gcr[0];
+ edat1 = ctlreg0.edat && test_vfacility(8);
+ edat2 = edat1 && test_vfacility(78);
+ asce.val = get_vcpu_asce(vcpu);
+ if (asce.r)
+ goto real_address;
+ ptr = asce.origin * 4096;
+ switch (asce.dt) {
+ case ASCE_TYPE_REGION1:
+ if (vaddr.rfx01 > asce.tl)
+ return PGM_REGION_FIRST_TRANS;
+ ptr += vaddr.rfx * 8;
+ break;
+ case ASCE_TYPE_REGION2:
+ if (vaddr.rfx)
+ return PGM_ASCE_TYPE;
+ if (vaddr.rsx01 > asce.tl)
+ return PGM_REGION_SECOND_TRANS;
+ ptr += vaddr.rsx * 8;
+ break;
+ case ASCE_TYPE_REGION3:
+ if (vaddr.rfx || vaddr.rsx)
+ return PGM_ASCE_TYPE;
+ if (vaddr.rtx01 > asce.tl)
+ return PGM_REGION_THIRD_TRANS;
+ ptr += vaddr.rtx * 8;
+ break;
+ case ASCE_TYPE_SEGMENT:
+ if (vaddr.rfx || vaddr.rsx || vaddr.rtx)
+ return PGM_ASCE_TYPE;
+ if (vaddr.sx01 > asce.tl)
+ return PGM_SEGMENT_TRANSLATION;
+ ptr += vaddr.sx * 8;
+ break;
+ }
+ switch (asce.dt) {
+ case ASCE_TYPE_REGION1: {
+ union region1_table_entry rfte;
+
+ if (kvm_is_error_gpa(vcpu->kvm, ptr))
+ return PGM_ADDRESSING;
+ if (deref_table(vcpu->kvm, ptr, &rfte.val))
+ return -EFAULT;
+ if (rfte.i)
+ return PGM_REGION_FIRST_TRANS;
+ if (rfte.tt != TABLE_TYPE_REGION1)
+ return PGM_TRANSLATION_SPEC;
+ if (vaddr.rsx01 < rfte.tf || vaddr.rsx01 > rfte.tl)
+ return PGM_REGION_SECOND_TRANS;
+ if (edat1)
+ dat_protection |= rfte.p;
+ ptr = rfte.rto * 4096 + vaddr.rsx * 8;
+ }
+ /* fallthrough */
+ case ASCE_TYPE_REGION2: {
+ union region2_table_entry rste;
+
+ if (kvm_is_error_gpa(vcpu->kvm, ptr))
+ return PGM_ADDRESSING;
+ if (deref_table(vcpu->kvm, ptr, &rste.val))
+ return -EFAULT;
+ if (rste.i)
+ return PGM_REGION_SECOND_TRANS;
+ if (rste.tt != TABLE_TYPE_REGION2)
+ return PGM_TRANSLATION_SPEC;
+ if (vaddr.rtx01 < rste.tf || vaddr.rtx01 > rste.tl)
+ return PGM_REGION_THIRD_TRANS;
+ if (edat1)
+ dat_protection |= rste.p;
+ ptr = rste.rto * 4096 + vaddr.rtx * 8;
+ }
+ /* fallthrough */
+ case ASCE_TYPE_REGION3: {
+ union region3_table_entry rtte;
+
+ if (kvm_is_error_gpa(vcpu->kvm, ptr))
+ return PGM_ADDRESSING;
+ if (deref_table(vcpu->kvm, ptr, &rtte.val))
+ return -EFAULT;
+ if (rtte.i)
+ return PGM_REGION_THIRD_TRANS;
+ if (rtte.tt != TABLE_TYPE_REGION3)
+ return PGM_TRANSLATION_SPEC;
+ if (rtte.cr && asce.p && edat2)
+ return PGM_TRANSLATION_SPEC;
+ if (rtte.fc && edat2) {
+ dat_protection |= rtte.fc1.p;
+ raddr.rfaa = rtte.fc1.rfaa;
+ goto absolute_address;
+ }
+ if (vaddr.sx01 < rtte.fc0.tf)
+ return PGM_SEGMENT_TRANSLATION;
+ if (vaddr.sx01 > rtte.fc0.tl)
+ return PGM_SEGMENT_TRANSLATION;
+ if (edat1)
+ dat_protection |= rtte.fc0.p;
+ ptr = rtte.fc0.sto * 4096 + vaddr.sx * 8;
+ }
+ /* fallthrough */
+ case ASCE_TYPE_SEGMENT: {
+ union segment_table_entry ste;
+
+ if (kvm_is_error_gpa(vcpu->kvm, ptr))
+ return PGM_ADDRESSING;
+ if (deref_table(vcpu->kvm, ptr, &ste.val))
+ return -EFAULT;
+ if (ste.i)
+ return PGM_SEGMENT_TRANSLATION;
+ if (ste.tt != TABLE_TYPE_SEGMENT)
+ return PGM_TRANSLATION_SPEC;
+ if (ste.cs && asce.p)
+ return PGM_TRANSLATION_SPEC;
+ if (ste.fc && edat1) {
+ dat_protection |= ste.fc1.p;
+ raddr.sfaa = ste.fc1.sfaa;
+ goto absolute_address;
+ }
+ dat_protection |= ste.fc0.p;
+ ptr = ste.fc0.pto * 2048 + vaddr.px * 8;
+ }
+ }
+ if (kvm_is_error_gpa(vcpu->kvm, ptr))
+ return PGM_ADDRESSING;
+ if (deref_table(vcpu->kvm, ptr, &pte.val))
+ return -EFAULT;
+ if (pte.i)
+ return PGM_PAGE_TRANSLATION;
+ if (pte.z)
+ return PGM_TRANSLATION_SPEC;
+ if (pte.co && !edat1)
+ return PGM_TRANSLATION_SPEC;
+ dat_protection |= pte.p;
+ raddr.pfra = pte.pfra;
+real_address:
+ raddr.addr = kvm_s390_real_to_abs(vcpu, raddr.addr);
+absolute_address:
+ if (write && dat_protection)
+ return PGM_PROTECTION;
+ if (kvm_is_error_gpa(vcpu->kvm, raddr.addr))
+ return PGM_ADDRESSING;
+ *gpa = raddr.addr;
+ return 0;
+}
+
+static inline int is_low_address(unsigned long ga)
+{
+ /* Check for address ranges 0..511 and 4096..4607 */
+ return (ga & ~0x11fful) == 0;
+}
+
+static int low_address_protection_enabled(struct kvm_vcpu *vcpu)
+{
+ union ctlreg0 ctlreg0 = {.val = vcpu->arch.sie_block->gcr[0]};
+ psw_t *psw = &vcpu->arch.sie_block->gpsw;
+ union asce asce;
+
+ if (!ctlreg0.lap)
+ return 0;
+ asce.val = get_vcpu_asce(vcpu);
+ if (psw_bits(*psw).t && asce.p)
+ return 0;
+ return 1;
+}
+
+struct trans_exc_code_bits {
+ unsigned long addr : 52; /* Translation-exception Address */
+ unsigned long fsi : 2; /* Access Exception Fetch/Store Indication */
+ unsigned long : 7;
+ unsigned long b61 : 1;
+ unsigned long as : 2; /* ASCE Identifier */
+};
+
+enum {
+ FSI_UNKNOWN = 0, /* Unknown wether fetch or store */
+ FSI_STORE = 1, /* Exception was due to store operation */
+ FSI_FETCH = 2 /* Exception was due to fetch operation */
+};
+
+static int guest_page_range(struct kvm_vcpu *vcpu, unsigned long ga,
+ unsigned long *pages, unsigned long nr_pages,
+ int write)
+{
+ struct kvm_s390_pgm_info *pgm = &vcpu->arch.pgm;
+ psw_t *psw = &vcpu->arch.sie_block->gpsw;
+ struct trans_exc_code_bits *tec_bits;
+ int lap_enabled, rc;
+
+ memset(pgm, 0, sizeof(*pgm));
+ tec_bits = (struct trans_exc_code_bits *)&pgm->trans_exc_code;
+ tec_bits->fsi = write ? FSI_STORE : FSI_FETCH;
+ tec_bits->as = psw_bits(*psw).as;
+ lap_enabled = low_address_protection_enabled(vcpu);
+ while (nr_pages) {
+ ga = kvm_s390_logical_to_effective(vcpu, ga);
+ tec_bits->addr = ga >> PAGE_SHIFT;
+ if (write && lap_enabled && is_low_address(ga)) {
+ pgm->code = PGM_PROTECTION;
+ return pgm->code;
+ }
+ ga &= PAGE_MASK;
+ if (psw_bits(*psw).t) {
+ rc = guest_translate(vcpu, ga, pages, write);
+ if (rc < 0)
+ return rc;
+ if (rc == PGM_PROTECTION)
+ tec_bits->b61 = 1;
+ if (rc)
+ pgm->code = rc;
+ } else {
+ *pages = kvm_s390_real_to_abs(vcpu, ga);
+ if (kvm_is_error_gpa(vcpu->kvm, *pages))
+ pgm->code = PGM_ADDRESSING;
+ }
+ if (pgm->code)
+ return pgm->code;
+ ga += PAGE_SIZE;
+ pages++;
+ nr_pages--;
+ }
+ return 0;
+}
+
+int access_guest(struct kvm_vcpu *vcpu, unsigned long ga, void *data,
+ unsigned long len, int write)
+{
+ psw_t *psw = &vcpu->arch.sie_block->gpsw;
+ unsigned long _len, nr_pages, gpa, idx;
+ unsigned long pages_array[2];
+ unsigned long *pages;
+ int rc;
+
+ if (!len)
+ return 0;
+ /* Access register mode is not supported yet. */
+ if (psw_bits(*psw).t && psw_bits(*psw).as == PSW_AS_ACCREG)
+ return -EOPNOTSUPP;
+ nr_pages = (((ga & ~PAGE_MASK) + len - 1) >> PAGE_SHIFT) + 1;
+ pages = pages_array;
+ if (nr_pages > ARRAY_SIZE(pages_array))
+ pages = vmalloc(nr_pages * sizeof(unsigned long));
+ if (!pages)
+ return -ENOMEM;
+ rc = guest_page_range(vcpu, ga, pages, nr_pages, write);
+ for (idx = 0; idx < nr_pages && !rc; idx++) {
+ gpa = *(pages + idx) + (ga & ~PAGE_MASK);
+ _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len);
+ if (write)
+ rc = kvm_write_guest(vcpu->kvm, gpa, data, _len);
+ else
+ rc = kvm_read_guest(vcpu->kvm, gpa, data, _len);
+ len -= _len;
+ ga += _len;
+ data += _len;
+ }
+ if (nr_pages > ARRAY_SIZE(pages_array))
+ vfree(pages);
+ return rc;
+}
+
+int access_guest_real(struct kvm_vcpu *vcpu, unsigned long gra,
+ void *data, unsigned long len, int write)
+{
+ unsigned long _len, gpa;
+ int rc = 0;
+
+ while (len && !rc) {
+ gpa = kvm_s390_real_to_abs(vcpu, gra);
+ _len = min(PAGE_SIZE - (gpa & ~PAGE_MASK), len);
+ if (write)
+ rc = write_guest_abs(vcpu, gpa, data, _len);
+ else
+ rc = read_guest_abs(vcpu, gpa, data, _len);
+ len -= _len;
+ gra += _len;
+ data += _len;
+ }
+ return rc;
+}
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