diff --git a/gdb/aarch64-linux-nat.c b/gdb/aarch64-linux-nat.c
index 86c7e87dd5..1fe3b83aac 100644
--- a/gdb/aarch64-linux-nat.c
+++ b/gdb/aarch64-linux-nat.c
@@ -45,6 +45,7 @@
 
 /* Defines ps_err_e, struct ps_prochandle.  */
 #include "gdb_proc_service.h"
+#include "arch-utils.h"
 
 #ifndef TRAP_HWBKPT
 #define TRAP_HWBKPT 0x0004
@@ -94,6 +95,8 @@ public:
   /* Add our siginfo layout converter.  */
   bool low_siginfo_fixup (siginfo_t *ptrace, gdb_byte *inf, int direction)
     override;
+
+  struct gdbarch *thread_architecture (ptid_t) override;
 };
 
 static aarch64_linux_nat_target the_aarch64_linux_nat_target;
@@ -939,6 +942,34 @@ aarch64_linux_nat_target::can_do_single_step ()
   return 1;
 }
 
+/* Implement the "thread_architecture" target_ops method.  */
+
+struct gdbarch *
+aarch64_linux_nat_target::thread_architecture (ptid_t ptid)
+{
+  /* Return the gdbarch for the current thread.  If the vector length has
+     changed since the last time this was called, then do a further lookup.  */
+
+  uint64_t vq = aarch64_sve_get_vq (ptid.lwp ());
+
+  /* Find the current gdbarch the same way as process_stratum_target.  Only
+     return it if the current vector length matches the one in the tdep.  */
+  inferior *inf = find_inferior_ptid (ptid);
+  gdb_assert (inf != NULL);
+  if (vq == gdbarch_tdep (inf->gdbarch)->vq)
+    return inf->gdbarch;
+
+  /* We reach here if the vector length for the thread is different from its
+     value at process start.  Lookup gdbarch via info (potentially creating a
+     new one), stashing the vector length inside id.  Use -1 for when SVE
+     unavailable, to distinguish from an unset value of 0.  */
+  struct gdbarch_info info;
+  gdbarch_info_init (&info);
+  info.bfd_arch_info = bfd_lookup_arch (bfd_arch_spu, bfd_mach_spu);
+  info.id = (int *) (vq == 0 ? -1 : vq);
+  return gdbarch_find_by_info (info);
+}
+
 /* Define AArch64 maintenance commands.  */
 
 static void
diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 3eb22a8502..737b430d48 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -3155,20 +3155,36 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   int i, num_regs = 0, num_pseudo_regs = 0;
   int first_pauth_regnum = -1, pauth_ra_state_offset = -1;
 
+  /* Use the vector length passed via the target info.  Here -1 is used for no
+     SVE, and 0 is unset.  If unset then use the vector length from the existing
+     tdesc.  */
+  uint64_t vq = 0;
+  if (info.id == (int *) -1)
+    vq = 0;
+  else if (info.id != 0)
+    vq = (uint64_t) info.id;
+  else
+    vq = aarch64_get_tdesc_vq (info.target_desc);
+
+  if (vq > AARCH64_MAX_SVE_VQ)
+    internal_error (__FILE__, __LINE__, _("VQ out of bounds: %ld (max %d)"),
+		    vq, AARCH64_MAX_SVE_VQ);
+
   /* If there is already a candidate, use it.  */
   for (gdbarch_list *best_arch = gdbarch_list_lookup_by_info (arches, &info);
        best_arch != nullptr;
        best_arch = gdbarch_list_lookup_by_info (best_arch->next, &info))
     {
       struct gdbarch_tdep *tdep = gdbarch_tdep (best_arch->gdbarch);
-      if (tdep)
+      if (tdep && tdep->vq == vq)
 	return best_arch->gdbarch;
     }
 
-  /* Ensure we always have a target description.  */
+  /* Ensure we always have a target descriptor, and that it is for the given VQ
+     value.  */
   const struct target_desc *tdesc = info.target_desc;
-  if (!tdesc_has_registers (tdesc))
-    tdesc = aarch64_read_description (0, false);
+  if (!tdesc_has_registers (tdesc) || vq != aarch64_get_tdesc_vq (tdesc))
+    tdesc = aarch64_read_description (vq, false);
   gdb_assert (tdesc);
 
   feature_core = tdesc_find_feature (tdesc,"org.gnu.gdb.aarch64.core");
@@ -3261,7 +3277,7 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   tdep->lowest_pc = 0x20;
   tdep->jb_pc = -1;		/* Longjump support not enabled by default.  */
   tdep->jb_elt_size = 8;
-  tdep->vq = aarch64_get_tdesc_vq (tdesc);
+  tdep->vq = vq;
   tdep->pauth_reg_base = first_pauth_regnum;
   tdep->pauth_ra_state_regnum = (feature_pauth == NULL) ? -1
 				: pauth_ra_state_offset + num_regs;
