microvm: memory config tweaks

-----BEGIN PGP SIGNATURE-----
 Version: GnuPG v2.0.22 (GNU/Linux)
 
 iQIcBAABCgAGBQJe6gx8AAoJEEy22O7T6HE4+9AP/ifAJaD8aAfzUe4OFZPGBELc
 cLLwq4EdEeq+WCYxbIIc3wQo2PY6PD/yHvPxtMApnMQjwyIiHyFFGe/TmbUc/s2w
 KZKiUU++X+eVGJwkWXijT7K0us11gs64k5n6YynV2cOAosl+YtAVk6Xd9FuJIc0y
 G/hEsGckkVVuSgHZBUt+HH8yaMjG2K10PQyiaUp0NoJbGv+Xviccds+H3pCNl6JD
 NCSRFNdVdb1sR5APgBDlmt/51oV/TaXMKpF4FBTzfLZCvcXBFkBaI1Z2hJQ25QM0
 9pSRA0GT/gQu69HuTMDZ6FZ9oH/w5gTkadvMeAZx8pyjQHkQWV3O3SP3eogSa+Up
 iAbg6JNzRZkaCReQoz8Gd9HgElSjYzlOsxiw2v7uXXIrEBLXGxKcMwdd9+Y/M2Lw
 aDHsI2T36KMVBPKGrcJgNPwKNZkHB6GulsYR47Zjcd3ASmQGmLD+KOhoL4cskMh+
 D3VxA8nJFQzdx+N3LTg2yYmolohyW6QN11mRcdkhsX+CjlpEmjVRvIDnYJSt3jf2
 5hdsKAxF9xKgk2oR6vXVUIllG24zxpP/cldB4U7tkSSBPRJvfZD44aD1vPI9ogpo
 NUaPllTWk39DkieiwMd2YtEKPEFIVKJWM51UvaNxWhInjAkeD+vx/iPSHkY6Cuje
 WWM485onOc3lzlYW+JZo
 =k1bm
 -----END PGP SIGNATURE-----

Merge remote-tracking branch 'remotes/kraxel/tags/microvm-20200617-pull-request' into staging

microvm: memory config tweaks

# gpg: Signature made Wed 17 Jun 2020 13:28:44 BST
# gpg:                using RSA key 4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>" [full]
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>" [full]
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>" [full]
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/microvm-20200617-pull-request:
  microvm: move virtio base to 0xfeb00000
  x86: move max-ram-below-4g to pc
  microvm: drop max-ram-below-4g support
  microvm: use 3G split unconditionally

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/i386/microvm.c

@@ -170,42 +170,9 @@ static void microvm_memory_init(MicrovmMachineState *mms)
     MemoryRegion *ram_below_4g, *ram_above_4g;
     MemoryRegion *system_memory = get_system_memory();
     FWCfgState *fw_cfg;
-    ram_addr_t lowmem;
+    ram_addr_t lowmem = 0xc0000000; /* 3G */
     int i;
 
-    /*
-     * Check whether RAM fits below 4G (leaving 1/2 GByte for IO memory
-     * and 256 Mbytes for PCI Express Enhanced Configuration Access Mapping
-     * also known as MMCFG).
-     * If it doesn't, we need to split it in chunks below and above 4G.
-     * In any case, try to make sure that guest addresses aligned at
-     * 1G boundaries get mapped to host addresses aligned at 1G boundaries.
-     */
-    if (machine->ram_size >= 0xb0000000) {
-        lowmem = 0x80000000;
-    } else {
-        lowmem = 0xb0000000;
-    }
-
-    /*
-     * Handle the machine opt max-ram-below-4g.  It is basically doing
-     * min(qemu limit, user limit).
-     */
-    if (!x86ms->max_ram_below_4g) {
-        x86ms->max_ram_below_4g = 4 * GiB;
-    }
-    if (lowmem > x86ms->max_ram_below_4g) {
-        lowmem = x86ms->max_ram_below_4g;
-        if (machine->ram_size - lowmem > lowmem &&
-            lowmem & (1 * GiB - 1)) {
-            warn_report("There is possibly poor performance as the ram size "
-                        " (0x%" PRIx64 ") is more then twice the size of"
-                        " max-ram-below-4g (%"PRIu64") and"
-                        " max-ram-below-4g is not a multiple of 1G.",
-                        (uint64_t)machine->ram_size, x86ms->max_ram_below_4g);
-        }
-    }
-
     if (machine->ram_size > lowmem) {
         x86ms->above_4g_mem_size = machine->ram_size - lowmem;
         x86ms->below_4g_mem_size = lowmem;

hw/i386/pc.c

@@ -1857,6 +1857,45 @@ static void pc_machine_set_pit(Object *obj, bool value, Error **errp)
     pcms->pit_enabled = value;
 }
 
+static void pc_machine_get_max_ram_below_4g(Object *obj, Visitor *v,
+                                            const char *name, void *opaque,
+                                            Error **errp)
+{
+    PCMachineState *pcms = PC_MACHINE(obj);
+    uint64_t value = pcms->max_ram_below_4g;
+
+    visit_type_size(v, name, &value, errp);
+}
+
+static void pc_machine_set_max_ram_below_4g(Object *obj, Visitor *v,
+                                            const char *name, void *opaque,
+                                            Error **errp)
+{
+    PCMachineState *pcms = PC_MACHINE(obj);
+    Error *error = NULL;
+    uint64_t value;
+
+    visit_type_size(v, name, &value, &error);
+    if (error) {
+        error_propagate(errp, error);
+        return;
+    }
+    if (value > 4 * GiB) {
+        error_setg(&error,
+                   "Machine option 'max-ram-below-4g=%"PRIu64
+                   "' expects size less than or equal to 4G", value);
+        error_propagate(errp, error);
+        return;
+    }
+
+    if (value < 1 * MiB) {
+        warn_report("Only %" PRIu64 " bytes of RAM below the 4GiB boundary,"
+                    "BIOS may not work with less than 1MiB", value);
+    }
+
+    pcms->max_ram_below_4g = value;
+}
+
 static void pc_machine_initfn(Object *obj)
 {
     PCMachineState *pcms = PC_MACHINE(obj);
@@ -1866,6 +1905,7 @@ static void pc_machine_initfn(Object *obj)
 #else
     pcms->vmport = ON_OFF_AUTO_OFF;
 #endif /* CONFIG_VMPORT */
+    pcms->max_ram_below_4g = 0; /* use default */
     /* acpi build is enabled by default if machine supports it */
     pcms->acpi_build_enabled = PC_MACHINE_GET_CLASS(pcms)->has_acpi_build;
     pcms->smbus_enabled = true;
@@ -1964,6 +2004,12 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
     mc->numa_mem_supported = true;
     mc->default_ram_id = "pc.ram";
 
+    object_class_property_add(oc, PC_MACHINE_MAX_RAM_BELOW_4G, "size",
+        pc_machine_get_max_ram_below_4g, pc_machine_set_max_ram_below_4g,
+        NULL, NULL);
+    object_class_property_set_description(oc, PC_MACHINE_MAX_RAM_BELOW_4G,
+        "Maximum ram below the 4G boundary (32bit boundary)");
+
     object_class_property_add(oc, PC_MACHINE_DEVMEM_REGION_SIZE, "int",
         pc_machine_get_device_memory_region_size, NULL,
         NULL, NULL);

hw/i386/pc_piix.c

@@ -129,11 +129,11 @@ static void pc_init1(MachineState *machine,
     if (xen_enabled()) {
         xen_hvm_init(pcms, &ram_memory);
     } else {
-        if (!x86ms->max_ram_below_4g) {
+        if (!pcms->max_ram_below_4g) {
-            x86ms->max_ram_below_4g = 0xe0000000; /* default: 3.5G */
+            pcms->max_ram_below_4g = 0xe0000000; /* default: 3.5G */
         }
-        lowmem = x86ms->max_ram_below_4g;
+        lowmem = pcms->max_ram_below_4g;
-        if (machine->ram_size >= x86ms->max_ram_below_4g) {
+        if (machine->ram_size >= pcms->max_ram_below_4g) {
             if (pcmc->gigabyte_align) {
                 if (lowmem > 0xc0000000) {
                     lowmem = 0xc0000000;
@@ -142,7 +142,7 @@ static void pc_init1(MachineState *machine,
                     warn_report("Large machine and max_ram_below_4g "
                                 "(%" PRIu64 ") not a multiple of 1G; "
                                 "possible bad performance.",
-                                x86ms->max_ram_below_4g);
+                                pcms->max_ram_below_4g);
                 }
             }
         }

hw/i386/pc_q35.c

@@ -156,18 +156,18 @@ static void pc_q35_init(MachineState *machine)
     /* Handle the machine opt max-ram-below-4g.  It is basically doing
      * min(qemu limit, user limit).
      */
-    if (!x86ms->max_ram_below_4g) {
+    if (!pcms->max_ram_below_4g) {
-        x86ms->max_ram_below_4g = 4 * GiB;
+        pcms->max_ram_below_4g = 4 * GiB;
     }
-    if (lowmem > x86ms->max_ram_below_4g) {
+    if (lowmem > pcms->max_ram_below_4g) {
-        lowmem = x86ms->max_ram_below_4g;
+        lowmem = pcms->max_ram_below_4g;
         if (machine->ram_size - lowmem > lowmem &&
             lowmem & (1 * GiB - 1)) {
             warn_report("There is possibly poor performance as the ram size "
                         " (0x%" PRIx64 ") is more then twice the size of"
                         " max-ram-below-4g (%"PRIu64") and"
                         " max-ram-below-4g is not a multiple of 1G.",
-                        (uint64_t)machine->ram_size, x86ms->max_ram_below_4g);
+                        (uint64_t)machine->ram_size, pcms->max_ram_below_4g);
         }
     }
 

hw/i386/x86.c

@@ -846,45 +846,6 @@ void x86_bios_rom_init(MemoryRegion *rom_memory, bool isapc_ram_fw)
                                 bios);
 }
 
-static void x86_machine_get_max_ram_below_4g(Object *obj, Visitor *v,
-                                             const char *name, void *opaque,
-                                             Error **errp)
-{
-    X86MachineState *x86ms = X86_MACHINE(obj);
-    uint64_t value = x86ms->max_ram_below_4g;
-
-    visit_type_size(v, name, &value, errp);
-}
-
-static void x86_machine_set_max_ram_below_4g(Object *obj, Visitor *v,
-                                             const char *name, void *opaque,
-                                             Error **errp)
-{
-    X86MachineState *x86ms = X86_MACHINE(obj);
-    Error *error = NULL;
-    uint64_t value;
-
-    visit_type_size(v, name, &value, &error);
-    if (error) {
-        error_propagate(errp, error);
-        return;
-    }
-    if (value > 4 * GiB) {
-        error_setg(&error,
-                   "Machine option 'max-ram-below-4g=%"PRIu64
-                   "' expects size less than or equal to 4G", value);
-        error_propagate(errp, error);
-        return;
-    }
-
-    if (value < 1 * MiB) {
-        warn_report("Only %" PRIu64 " bytes of RAM below the 4GiB boundary,"
-                    "BIOS may not work with less than 1MiB", value);
-    }
-
-    x86ms->max_ram_below_4g = value;
-}
-
 bool x86_machine_is_smm_enabled(X86MachineState *x86ms)
 {
     bool smm_available = false;
@@ -958,7 +919,6 @@ static void x86_machine_initfn(Object *obj)
 
     x86ms->smm = ON_OFF_AUTO_AUTO;
     x86ms->acpi = ON_OFF_AUTO_AUTO;
-    x86ms->max_ram_below_4g = 0; /* use default */
     x86ms->smp_dies = 1;
 
     x86ms->apicid_from_cpu_idx = x86_apicid_from_cpu_idx;
@@ -980,12 +940,6 @@ static void x86_machine_class_init(ObjectClass *oc, void *data)
     x86mc->save_tsc_khz = true;
     nc->nmi_monitor_handler = x86_nmi;
 
-    object_class_property_add(oc, X86_MACHINE_MAX_RAM_BELOW_4G, "size",
-        x86_machine_get_max_ram_below_4g, x86_machine_set_max_ram_below_4g,
-        NULL, NULL);
-    object_class_property_set_description(oc, X86_MACHINE_MAX_RAM_BELOW_4G,
-        "Maximum ram below the 4G boundary (32bit boundary)");
-
     object_class_property_add(oc, X86_MACHINE_SMM, "OnOffAuto",
         x86_machine_get_smm, x86_machine_set_smm,
         NULL, NULL);

hw/i386/xen/xen-hvm.c

@@ -205,7 +205,7 @@ static void xen_ram_init(PCMachineState *pcms,
     ram_addr_t block_len;
     uint64_t user_lowmem =
         object_property_get_uint(qdev_get_machine(),
-                                 X86_MACHINE_MAX_RAM_BELOW_4G,
+                                 PC_MACHINE_MAX_RAM_BELOW_4G,
                                  &error_abort);
 
     /* Handle the machine opt max-ram-below-4g.  It is basically doing

include/hw/i386/microvm.h

@@ -26,7 +26,7 @@
 #include "hw/i386/x86.h"
 
 /* Platform virtio definitions */
-#define VIRTIO_MMIO_BASE      0xc0000000
+#define VIRTIO_MMIO_BASE      0xfeb00000
 #define VIRTIO_IRQ_BASE       5
 #define VIRTIO_NUM_TRANSPORTS 8
 #define VIRTIO_CMDLINE_MAXLEN 64

include/hw/i386/pc.h

@@ -35,6 +35,7 @@ struct PCMachineState {
     PFlashCFI01 *flash[2];
 
     /* Configuration options: */
+    uint64_t max_ram_below_4g;
     OnOffAuto vmport;
 
     bool acpi_build_enabled;
@@ -51,6 +52,7 @@ struct PCMachineState {
 };
 
 #define PC_MACHINE_ACPI_DEVICE_PROP "acpi-device"
+#define PC_MACHINE_MAX_RAM_BELOW_4G "max-ram-below-4g"
 #define PC_MACHINE_DEVMEM_REGION_SIZE "device-memory-region-size"
 #define PC_MACHINE_VMPORT           "vmport"
 #define PC_MACHINE_SMBUS            "smbus"

include/hw/i386/x86.h

@@ -51,9 +51,6 @@ typedef struct {
     qemu_irq *gsi;
     GMappedFile *initrd_mapped_file;
 
-    /* Configuration options: */
-    uint64_t max_ram_below_4g;
-
     /* RAM information (sizes, addresses, configuration): */
     ram_addr_t below_4g_mem_size, above_4g_mem_size;
 
@@ -82,7 +79,6 @@ typedef struct {
     AddressSpace *ioapic_as;
 } X86MachineState;
 
-#define X86_MACHINE_MAX_RAM_BELOW_4G "max-ram-below-4g"
 #define X86_MACHINE_SMM              "smm"
 #define X86_MACHINE_ACPI             "acpi"