[v6] tests/avocado: add test to exercize processor address space memory bound checks

diff --git a/tests/avocado/mem-addr-space-check.py b/tests/avocado/mem-addr-space-check.py
new file mode 100644
index 0000000000..fae7d48598
--- /dev/null
+++ b/tests/avocado/mem-addr-space-check.py
@@ -0,0 +1,367 @@ 
+# Check for crash when using memory beyond the available guest processor
+# address space.
+#
+# Copyright (c) 2023 Red Hat, Inc.
+#
+# Author:
+#  Ani Sinha <anisinha@redhat.com>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from avocado_qemu import QemuSystemTest
+import signal
+import time
+
+class MemAddrCheck(QemuSystemTest):
+    # after launch, in order to generate the logs from QEMU we need to
+    # wait for some time. Launching and then immediately shutting down
+    # the VM generates empty logs. A delay of 1 second is added for
+    # this reason.
+    DELAY_Q35_BOOT_SEQUENCE = 1
+
+    # first, lets test some 32-bit processors.
+    # for all 32-bit cases, pci64_hole_size is 0.
+    def test_phybits_low_pse36(self):
+        """
+        :avocado: tags=machine:q35
+        :avocado: tags=arch:x86_64
+
+        With pse36 feature ON, a processor has 36 bits of addressing. So it can
+        access up to a maximum of 64GiB of memory. Memory hotplug region begins
+        at 4 GiB boundary when "above_4g_mem_size" is 0 (this would be true when
+        we have 0.5 GiB of VM memory, see pc_q35_init()). This means total
+        hotpluggable memory size is 60 GiB. Per slot, we reserve 1 GiB of memory
+        for dimm alignment for all newer machines (see enforce_aligned_dimm
+        property for pc machines and pc_get_device_memory_range()). That leaves
+        total hotpluggable actual memory size of 59 GiB. If the VM is started
+        with 0.5 GiB of memory, maxmem should be set to a maximum value of
+        59.5 GiB to ensure that the processor can address all memory directly.
+        Note that 64-bit pci hole size is 0 in this case. If maxmem is set to
+        59.6G, QEMU should fail to start with a message "phy-bits are too low".
+        If maxmem is set to 59.5G with all other QEMU parameters identical, QEMU
+        should start fine.
+        """
+        self.vm.add_args('-S', '-machine', 'q35', '-m',
+                         '512,slots=1,maxmem=59.6G',
+                         '-cpu', 'pentium,pse36=on', '-display', 'none',
+                         '-object', 'memory-backend-ram,id=mem1,size=1G',
+                         '-device', 'pc-dimm,id=vm0,memdev=mem1')
+        self.vm.set_qmp_monitor(enabled=False)
+        self.vm.launch()
+        self.vm.wait()
+        self.assertEquals(self.vm.exitcode(), 1, "QEMU exit code should be 1")
+        self.assertRegex(self.vm.get_log(), r'phys-bits too low')
+
+    def test_phybits_low_pae(self):
+        """
+        :avocado: tags=machine:q35
+        :avocado: tags=arch:x86_64
+
+        With pae feature ON, a processor has 36 bits of addressing. So it can
+        access up to a maximum of 64GiB of memory. Rest is the same as the case
+        with pse36 above.
+        """
+        self.vm.add_args('-S', '-machine', 'q35', '-m',
+                         '512,slots=1,maxmem=59.6G',
+                         '-cpu', 'pentium,pae=on', '-display', 'none',
+                         '-object', 'memory-backend-ram,id=mem1,size=1G',
+                         '-device', 'pc-dimm,id=vm0,memdev=mem1')
+        self.vm.set_qmp_monitor(enabled=False)
+        self.vm.launch()
+        self.vm.wait()
+        self.assertEquals(self.vm.exitcode(), 1, "QEMU exit code should be 1")
+        self.assertRegex(self.vm.get_log(), r'phys-bits too low')
+
+    def test_phybits_ok_pentium_pse36(self):
+        """
+        :avocado: tags=machine:q35
+        :avocado: tags=arch:x86_64
+
+        Setting maxmem to 59.5G and making sure that QEMU can start with the
+        same options as the failing case above with pse36 cpu feature.
+        """
+        self.vm.add_args('-machine', 'q35', '-m',
+                         '512,slots=1,maxmem=59.5G',
+                         '-cpu', 'pentium,pse36=on', '-display', 'none',
+                         '-object', 'memory-backend-ram,id=mem1,size=1G',
+                         '-device', 'pc-dimm,id=vm0,memdev=mem1')
+        self.vm.set_qmp_monitor(enabled=False)
+        self.vm.launch()
+        time.sleep(self.DELAY_Q35_BOOT_SEQUENCE)
+        self.vm.shutdown()
+        self.assertNotRegex(self.vm.get_log(), r'phys-bits too low')
+
+    def test_phybits_ok_pentium_pae(self):
+        """
+        :avocado: tags=machine:q35
+        :avocado: tags=arch:x86_64
+
+        Test is same as above but now with pae cpu feature turned on.
+        Setting maxmem to 59.5G and making sure that QEMU can start fine
+        with the same options as the case above.
+        """
+        self.vm.add_args('-machine', 'q35', '-m',
+                         '512,slots=1,maxmem=59.5G',
+                         '-cpu', 'pentium,pae=on', '-display', 'none',
+                         '-object', 'memory-backend-ram,id=mem1,size=1G',
+                         '-device', 'pc-dimm,id=vm0,memdev=mem1')
+        self.vm.set_qmp_monitor(enabled=False)
+        self.vm.launch()
+        time.sleep(self.DELAY_Q35_BOOT_SEQUENCE)
+        self.vm.shutdown()
+        self.assertNotRegex(self.vm.get_log(), r'phys-bits too low')
+
+    def test_phybits_ok_pentium2(self):
+        """
+        :avocado: tags=machine:q35
+        :avocado: tags=arch:x86_64
+
+        Pentium2 has 36 bits of addressing, so its same as pentium
+        with pse36 ON.
+        """
+        self.vm.add_args('-machine', 'q35', '-m',
+                         '512,slots=1,maxmem=59.5G',
+                         '-cpu', 'pentium2', '-display', 'none',
+                         '-object', 'memory-backend-ram,id=mem1,size=1G',
+                         '-device', 'pc-dimm,id=vm0,memdev=mem1')
+        self.vm.set_qmp_monitor(enabled=False)
+        self.vm.launch()
+        time.sleep(self.DELAY_Q35_BOOT_SEQUENCE)
+        self.vm.shutdown()
+        self.assertNotRegex(self.vm.get_log(), r'phys-bits too low')
+
+    def test_phybits_low_nonpse36(self):
+        """
+        :avocado: tags=machine:q35
+        :avocado: tags=arch:x86_64
+
+        Pentium processor has 32 bits of addressing without pse36 or pae
+        so it can access physical address up to 4 GiB. Setting maxmem to
+        4 GiB should make QEMU fail to start with "phys-bits too low"
+        message because the region for memory hotplug is always placed
+        above 4 GiB due to the PCI hole and simplicity.
+        """
+        self.vm.add_args('-S', '-machine', 'q35', '-m',
+                         '512,slots=1,maxmem=4G',
+                         '-cpu', 'pentium', '-display', 'none',
+                         '-object', 'memory-backend-ram,id=mem1,size=1G',
+                         '-device', 'pc-dimm,id=vm0,memdev=mem1')
+        self.vm.set_qmp_monitor(enabled=False)
+        self.vm.launch()
+        self.vm.wait()
+        self.assertEquals(self.vm.exitcode(), 1, "QEMU exit code should be 1")
+        self.assertRegex(self.vm.get_log(), r'phys-bits too low')
+
+    # now lets test some 64-bit CPU cases.
+    def test_phybits_low_tcg_q35_70_amd(self):
+        """
+        :avocado: tags=machine:q35
+        :avocado: tags=arch:x86_64
+
+        For q35 7.1 machines and above, there is a HT window that starts at
+        1024 GiB and ends at 1 TiB - 1. If the max GPA falls in this range,
+        "above_4G" memory is adjusted to start at 1 TiB boundary for AMD cpus
+        in the default case. Lets test without that case for machines 7.0.
+        For q35-7.0 machines, "above 4G" memory starts are 4G.
+        pci64_hole size is 32 GiB. Since TCG_PHYS_ADDR_BITS is defined to
+        be 40, TCG emulated CPUs have maximum of 1 TiB (1024 GiB) of
+        directly addressible memory.
+        Hence, maxmem value at most can be
+        1024 GiB - 4 GiB - 1 GiB per slot for alignment - 32 GiB + 0.5 GiB
+        which is equal to 987.5 GiB. Setting the value to 988 GiB should
+        make QEMU fail with the error message.
+        """
+        self.vm.add_args('-S', '-machine', 'pc-q35-7.0', '-m',
+                         '512,slots=1,maxmem=988G',
+                         '-display', 'none',
+                         '-object', 'memory-backend-ram,id=mem1,size=1G',
+                         '-device', 'pc-dimm,id=vm0,memdev=mem1')
+        self.vm.set_qmp_monitor(enabled=False)
+        self.vm.launch()
+        self.vm.wait()
+        self.assertEquals(self.vm.exitcode(), 1, "QEMU exit code should be 1")
+        self.assertRegex(self.vm.get_log(), r'phys-bits too low')
+
+    def test_phybits_low_tcg_q35_71_amd(self):
+        """
+        :avocado: tags=machine:q35
+        :avocado: tags=arch:x86_64
+
+        AMD_HT_START is defined to be at 1012 GiB. So for q35 machines
+        version > 7.0 and AMD cpus, instead of 1024 GiB limit for 40 bit
+        processor address space, it has to be 1012 GiB , that is 12 GiB
+        less than the case above in order to accomodate HT hole.
+        Make sure QEMU fails when maxmem size is 976 GiB (12 GiB less
+        than 988 GiB).
+        """
+        self.vm.add_args('-S', '-machine', 'pc-q35-7.1', '-m',
+                         '512,slots=1,maxmem=976G',
+                         '-display', 'none',
+                         '-object', 'memory-backend-ram,id=mem1,size=1G',
+                         '-device', 'pc-dimm,id=vm0,memdev=mem1')
+        self.vm.set_qmp_monitor(enabled=False)
+        self.vm.launch()
+        self.vm.wait()
+        self.assertEquals(self.vm.exitcode(), 1, "QEMU exit code should be 1")
+        self.assertRegex(self.vm.get_log(), r'phys-bits too low')
+
+    def test_phybits_ok_tcg_q35_70_amd(self):
+        """
+        :avocado: tags=machine:q35
+        :avocado: tags=arch:x86_64
+
+        Same as q35-7.0 AMD case except that here we check that QEMU can
+        successfully start when maxmem is < 988G.
+        """
+        self.vm.add_args('-S', '-machine', 'pc-q35-7.0', '-m',
+                         '512,slots=1,maxmem=987.5G',
+                         '-display', 'none',
+                         '-object', 'memory-backend-ram,id=mem1,size=1G',
+                         '-device', 'pc-dimm,id=vm0,memdev=mem1')
+        self.vm.set_qmp_monitor(enabled=False)
+        self.vm.launch()
+        time.sleep(self.DELAY_Q35_BOOT_SEQUENCE)
+        self.vm.shutdown()
+        self.assertNotRegex(self.vm.get_log(), r'phys-bits too low')
+
+    def test_phybits_ok_tcg_q35_71_amd(self):
+        """
+        :avocado: tags=machine:q35
+        :avocado: tags=arch:x86_64
+
+        Same as q35-7.1 AMD case except that here we check that QEMU can
+        successfully start when maxmem is < 976G.
+        """
+        self.vm.add_args('-S', '-machine', 'pc-q35-7.1', '-m',
+                         '512,slots=1,maxmem=975.5G',
+                         '-display', 'none',
+                         '-object', 'memory-backend-ram,id=mem1,size=1G',
+                         '-device', 'pc-dimm,id=vm0,memdev=mem1')
+        self.vm.set_qmp_monitor(enabled=False)
+        self.vm.launch()
+        time.sleep(self.DELAY_Q35_BOOT_SEQUENCE)
+        self.vm.shutdown()
+        self.assertNotRegex(self.vm.get_log(), r'phys-bits too low')
+
+    def test_phybits_ok_tcg_q35_71_intel(self):
+        """
+        :avocado: tags=machine:q35
+        :avocado: tags=arch:x86_64
+
+        Same parameters as test_phybits_low_tcg_q35_71_amd() but use
+        Intel cpu instead. QEMU should start fine in this case as
+        "above_4G" memory starts at 4G.
+        """
+        self.vm.add_args('-S', '-cpu', 'Skylake-Server',
+                         '-machine', 'pc-q35-7.1', '-m',
+                         '512,slots=1,maxmem=976G',
+                         '-display', 'none',
+                         '-object', 'memory-backend-ram,id=mem1,size=1G',
+                         '-device', 'pc-dimm,id=vm0,memdev=mem1')
+        self.vm.set_qmp_monitor(enabled=False)
+        self.vm.launch()
+        time.sleep(self.DELAY_Q35_BOOT_SEQUENCE)
+        self.vm.shutdown()
+        self.assertNotRegex(self.vm.get_log(), r'phys-bits too low')
+
+    def test_phybits_low_tcg_q35_71_amd_41bits(self):
+        """
+        :avocado: tags=machine:q35
+        :avocado: tags=arch:x86_64
+
+        AMD processor with 41 bits. Max cpu hw address = 2 TiB.
+        By setting maxram above 1012 GiB  - 32 GiB - 4 GiB = 976 GiB, we can
+        force "above_4G" memory to start at 1 TiB for q35-7.1 machines
+        (max GPA will be above AMD_HT_START which is defined as 1012 GiB).
+
+        With pci_64_hole size at 32 GiB, in this case, maxmem should be 991.5
+        GiB with 1 GiB per slot for alignment and 0.5 GiB as non-hotplug
+        memory for the VM (1024 - 32 - 1 + 0.5). With 992 GiB, QEMU should
+        fail to start.
+        """
+        self.vm.add_args('-S', '-cpu', 'EPYC-v4,phys-bits=41',
+                         '-machine', 'pc-q35-7.1', '-m',
+                         '512,slots=1,maxmem=992G',
+                         '-display', 'none',
+                         '-object', 'memory-backend-ram,id=mem1,size=1G',
+                         '-device', 'pc-dimm,id=vm0,memdev=mem1')
+        self.vm.set_qmp_monitor(enabled=False)
+        self.vm.launch()
+        self.vm.wait()
+        self.assertEquals(self.vm.exitcode(), 1, "QEMU exit code should be 1")
+        self.assertRegex(self.vm.get_log(), r'phys-bits too low')
+
+    def test_phybits_ok_tcg_q35_71_amd_41bits(self):
+        """
+        :avocado: tags=machine:q35
+        :avocado: tags=arch:x86_64
+
+        AMD processor with 41 bits. Max cpu hw address = 2 TiB.
+        Same as above but by setting maxram beween 976 GiB and 992 Gib,
+        QEMU should start fine.
+        """
+        self.vm.add_args('-S', '-cpu', 'EPYC-v4,phys-bits=41',
+                         '-machine', 'pc-q35-7.1', '-m',
+                         '512,slots=1,maxmem=990G',
+                         '-display', 'none',
+                         '-object', 'memory-backend-ram,id=mem1,size=1G',
+                         '-device', 'pc-dimm,id=vm0,memdev=mem1')
+        self.vm.set_qmp_monitor(enabled=False)
+        self.vm.launch()
+        time.sleep(self.DELAY_Q35_BOOT_SEQUENCE)
+        self.vm.shutdown()
+        self.assertNotRegex(self.vm.get_log(), r'phys-bits too low')
+
+    def test_phybits_low_tcg_q35_intel_cxl(self):
+        """
+        :avocado: tags=machine:q35
+        :avocado: tags=arch:x86_64
+
+        cxl memory window starts after memory device range. Here, we use 1 GiB
+        of cxl window memory. 4G_mem end aligns at 4G. pci64_hole is 32 GiB and
+        starts after the cxl memory window.
+        So maxmem here should be at most 986 GiB considering all memory boundary
+        alignment constraints with 40 bits (1 TiB) of processor physical bits.
+        """
+        self.vm.add_args('-S', '-cpu', 'Skylake-Server,phys-bits=40',
+                         '-machine', 'q35,cxl=on', '-m',
+                         '512,slots=1,maxmem=987G',
+                         '-display', 'none',
+                         '-device', 'pxb-cxl,bus_nr=12,bus=pcie.0,id=cxl.1',
+                         '-M', 'cxl-fmw.0.targets.0=cxl.1,cxl-fmw.0.size=1G')
+        self.vm.set_qmp_monitor(enabled=False)
+        self.vm.launch()
+        self.vm.wait()
+        self.assertEquals(self.vm.exitcode(), 1, "QEMU exit code should be 1")
+        self.assertRegex(self.vm.get_log(), r'phys-bits too low')
+
+    def test_phybits_ok_tcg_q35_intel_cxl(self):
+        """
+        :avocado: tags=machine:q35
+        :avocado: tags=arch:x86_64
+
+        Same as above but here we do not reserve any cxl memory window. Hence,
+        with the exact same parameters as above, QEMU should start fine even
+        with cxl enabled.
+        """
+        self.vm.add_args('-S', '-cpu', 'Skylake-Server,phys-bits=40',
+                         '-machine', 'q35,cxl=on', '-m',
+                         '512,slots=1,maxmem=987G',
+                         '-display', 'none',
+                         '-device', 'pxb-cxl,bus_nr=12,bus=pcie.0,id=cxl.1')
+        self.vm.set_qmp_monitor(enabled=False)
+        self.vm.launch()
+        time.sleep(self.DELAY_Q35_BOOT_SEQUENCE)
+        self.vm.shutdown()
+        self.assertNotRegex(self.vm.get_log(), r'phys-bits too low')