In case the call to mmap fails, we log an error and abort to signal
there is something wrong with the system.
Check the register page version and compare with the expected version and
abort in case of a mismatch.

Fixes: a173f8f170
Signed-off-by: Doru Blânzeanu <dblanzeanu@linux.microsoft.com>
---
 target/i386/mshv/mshv-cpu.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/target/i386/mshv/mshv-cpu.c b/target/i386/mshv/mshv-cpu.c
index 126ca40b48..3d92d4dbad 100644
--- a/target/i386/mshv/mshv-cpu.c
+++ b/target/i386/mshv/mshv-cpu.c
@@ -2049,6 +2049,7 @@ void mshv_arch_init_vcpu(CPUState *cpu)
     CPUX86State *env = &x86_cpu->env;
     AccelCPUState *state = cpu->accel;
     size_t page = HV_HYP_PAGE_SIZE, xsave_len;
+    void *regs_page;
     void *mem = qemu_memalign(page, 2 * page);
     int ret;
     X86XSaveHeader *header;
@@ -2060,15 +2061,20 @@ void mshv_arch_init_vcpu(CPUState *cpu)
                       > HV_HYP_PAGE_SIZE));
 
     /* mmap the registers page */
-    void *rp = mmap(NULL, page, PROT_READ | PROT_WRITE,
+    regs_page = mmap(NULL, page, PROT_READ | PROT_WRITE,
                     MAP_SHARED, mshv_vcpufd(cpu),
                     MSHV_VP_MMAP_OFFSET_REGISTERS * page);
-    if (rp == MAP_FAILED) {
-        warn_report("register page mmap failed, falling back to hypercalls: %s",
-                    strerror(errno));
-        env->regs_page = NULL;
-    } else {
-        env->regs_page = (struct hv_vp_register_page *) rp;
+    if (regs_page == MAP_FAILED) {
+        /* This shouldn't fail, so we treat it as a fatal error */
+        error_report("register page mmap failed: %s", strerror(errno));
+        abort();
+    }
+    env->regs_page = (struct hv_vp_register_page *) regs_page;
+
+    if (env->regs_page->version != HV_VP_REGISTER_PAGE_VERSION_1) {
+        error_report("register page version mismatch: got %u, expected %u",
+                     env->regs_page->version, HV_VP_REGISTER_PAGE_VERSION_1);
+        abort();
     }
 
     state->hvcall_args.base = mem;
-- 
2.53.0