Allow the user to specify the RAM base address by using -m/--mem size@addr
command line argument. The base address must be above 2GB, as to not
overlap with the MMIO I/O region.

Signed-off-by: Alexandru Elisei <alexandru.eli...@arm.com>
---
 arm/aarch64/include/kvm/kvm-arch.h |  2 ++
 arm/aarch64/kvm.c                  | 14 ++++++++----
 arm/kvm.c                          |  7 ++++--
 builtin-run.c                      | 36 ++++++++++++++++++++++++++----
 include/kvm/kvm-config.h           |  1 +
 include/kvm/kvm.h                  | 12 ++++++++++
 include/linux/sizes.h              |  2 ++
 7 files changed, 64 insertions(+), 10 deletions(-)

diff --git a/arm/aarch64/include/kvm/kvm-arch.h 
b/arm/aarch64/include/kvm/kvm-arch.h
index ff857ca6e7b4..02d09a413831 100644
--- a/arm/aarch64/include/kvm/kvm-arch.h
+++ b/arm/aarch64/include/kvm/kvm-arch.h
@@ -10,6 +10,8 @@ void kvm__arch_enable_mte(struct kvm *kvm);
 
 #define MAX_PAGE_SIZE  SZ_64K
 
+#define ARCH_HAS_CFG_RAM_ADDRESS       1
+
 #include "arm-common/kvm-arch.h"
 
 #endif /* KVM__KVM_ARCH_H */
diff --git a/arm/aarch64/kvm.c b/arm/aarch64/kvm.c
index 357936844046..54200c9eec9d 100644
--- a/arm/aarch64/kvm.c
+++ b/arm/aarch64/kvm.c
@@ -4,6 +4,7 @@
 
 #include <linux/byteorder.h>
 #include <linux/cpumask.h>
+#include <linux/sizes.h>
 
 #include <kvm/util.h>
 
@@ -39,10 +40,15 @@ int vcpu_affinity_parser(const struct option *opt, const 
char *arg, int unset)
 
 void kvm__arch_validate_cfg(struct kvm *kvm)
 {
+
+       if (kvm->cfg.ram_addr < ARM_MEMORY_AREA) {
+               die("RAM address is below the I/O region ending at %luGB",
+                   ARM_MEMORY_AREA >> 30);
+       }
+
        if (kvm->cfg.arch.aarch32_guest &&
-           kvm->cfg.ram_size > ARM_LOMAP_MAX_MEMORY) {
-               die("RAM size 0x%llx exceeds maximum allowed 0x%llx",
-                   kvm->cfg.ram_size, ARM_LOMAP_MAX_MEMORY);
+           kvm->cfg.ram_addr + kvm->cfg.ram_size > SZ_4G) {
+               die("RAM extends above 4GB");
        }
 }
 
@@ -117,7 +123,7 @@ int kvm__get_vm_type(struct kvm *kvm)
                return 0;
 
        /* Otherwise, compute the minimal required IPA size */
-       max_ipa = ARM_MEMORY_AREA + kvm->cfg.ram_size - 1;
+       max_ipa = kvm->cfg.ram_addr + kvm->cfg.ram_size - 1;
        ipa_bits = max(32, fls_long(max_ipa));
        pr_debug("max_ipa %lx ipa_bits %d max_ipa_bits %d",
                 max_ipa, ipa_bits, max_ipa_bits);
diff --git a/arm/kvm.c b/arm/kvm.c
index abcccfabf59e..d51cc15d8b1c 100644
--- a/arm/kvm.c
+++ b/arm/kvm.c
@@ -55,7 +55,7 @@ void kvm__init_ram(struct kvm *kvm)
        madvise(kvm->arch.ram_alloc_start, kvm->arch.ram_alloc_size,
                MADV_HUGEPAGE);
 
-       phys_start      = ARM_MEMORY_AREA;
+       phys_start      = kvm->cfg.ram_addr;
        phys_size       = kvm->ram_size;
        host_mem        = kvm->ram_start;
 
@@ -65,6 +65,9 @@ void kvm__init_ram(struct kvm *kvm)
                    "address 0x%llx [err %d]", phys_size, phys_start, err);
 
        kvm->arch.memory_guest_start = phys_start;
+
+       pr_debug("RAM created at 0x%llx - 0x%llx",
+                phys_start, phys_start + phys_size - 1);
 }
 
 void kvm__arch_delete_ram(struct kvm *kvm)
@@ -201,7 +204,7 @@ bool kvm__load_firmware(struct kvm *kvm, const char 
*firmware_filename)
 
        /* For default firmware address, lets load it at the begining of RAM */
        if (fw_addr == 0)
-               fw_addr = ARM_MEMORY_AREA;
+               fw_addr = kvm->arch.memory_guest_start;
 
        if (!validate_fw_addr(kvm, fw_addr))
                die("Bad firmware destination: 0x%016llx", fw_addr);
diff --git a/builtin-run.c b/builtin-run.c
index a49698d5b2fe..68beaaa7c06f 100644
--- a/builtin-run.c
+++ b/builtin-run.c
@@ -131,12 +131,21 @@ static u64 parse_mem_option(const char *nptr, char **next)
 static int mem_parser(const struct option *opt, const char *arg, int unset)
 {
        struct kvm *kvm = opt->ptr;
-       char *next;
+       char *next, *nptr;
 
        kvm->cfg.ram_size = parse_mem_option(arg, &next);
        if (kvm->cfg.ram_size == 0)
                die("Invalid RAM size: %s", arg);
 
+       if (kvm__arch_has_cfg_ram_address() && *next == '@') {
+               next++;
+               if (*next == '\0')
+                       die("Missing memory address: %s", arg);
+
+               nptr = next;
+               kvm->cfg.ram_addr = parse_mem_option(nptr, &next);
+       }
+
        if (*next != '\0')
                die("Invalid memory specifier: %s", arg);
 
@@ -147,15 +156,26 @@ static int mem_parser(const struct option *opt, const 
char *arg, int unset)
 #define OPT_ARCH_RUN(...)
 #endif
 
+#ifdef ARCH_HAS_CFG_RAM_ADDRESS
+#define MEM_OPT_HELP_SHORT     "size[BKMGTP][@addr[BKMGTP]]"
+#define MEM_OPT_HELP_LONG                                              \
+       "Virtual machine memory size and optional base address, both"   \
+       " measured by default in megabytes (M)"
+#else
+#define MEM_OPT_HELP_SHORT     "size[BKMGTP]"
+#define MEM_OPT_HELP_LONG                                              \
+       "Virtual machine memory size, by default measured in"           \
+       " in megabytes (M)"
+#endif
+
 #define BUILD_OPTIONS(name, cfg, kvm)                                  \
        struct option name[] = {                                        \
        OPT_GROUP("Basic options:"),                                    \
        OPT_STRING('\0', "name", &(cfg)->guest_name, "guest name",      \
                        "A name for the guest"),                        \
        OPT_INTEGER('c', "cpus", &(cfg)->nrcpus, "Number of CPUs"),     \
-       OPT_CALLBACK('m', "mem", NULL, "size[BKMGTP]",                  \
-                    "Virtual machine memory size, by default measured" \
-                    " in megabytes (M)", mem_parser, kvm),             \
+       OPT_CALLBACK('m', "mem", NULL, MEM_OPT_HELP_SHORT,              \
+                    MEM_OPT_HELP_LONG, mem_parser, kvm),               \
        OPT_CALLBACK('d', "disk", kvm, "image or rootfs_dir", "Disk "   \
                        " image or rootfs directory", img_name_parser,  \
                        kvm),                                           \
@@ -601,6 +621,14 @@ static struct kvm *kvm_cmd_run_init(int argc, const char 
**argv)
 
        nr_online_cpus = sysconf(_SC_NPROCESSORS_ONLN);
        kvm->cfg.custom_rootfs_name = "default";
+       /*
+        * An architecture might allow the user to set the RAM base address to
+        * zero. Initialize the address before parsing the command line
+        * arguments, because otherwise it will be impossible to distinguish
+        * between the user setting the base address to zero or letting it
+        * unspecified.
+        */
+       kvm->cfg.ram_addr = kvm__arch_default_ram_address();
 
        while (argc != 0) {
                BUILD_OPTIONS(options, &kvm->cfg, kvm);
diff --git a/include/kvm/kvm-config.h b/include/kvm/kvm-config.h
index 31bc89520d52..45fe1caaebce 100644
--- a/include/kvm/kvm-config.h
+++ b/include/kvm/kvm-config.h
@@ -23,6 +23,7 @@ struct kvm_config {
        struct kvm_config_arch arch;
        struct disk_image_params disk_image[MAX_DISK_IMAGES];
        struct vfio_device_params *vfio_devices;
+       u64 ram_addr;           /* Guest memory physical base address, in bytes 
*/
        u64 ram_size;           /* Guest memory size, in bytes */
        u8 num_net_devices;
        u8 num_vfio_devices;
diff --git a/include/kvm/kvm.h b/include/kvm/kvm.h
index 360430b78b1e..eb23e2f77310 100644
--- a/include/kvm/kvm.h
+++ b/include/kvm/kvm.h
@@ -197,6 +197,18 @@ int kvm__arch_free_firmware(struct kvm *kvm);
 bool kvm__arch_cpu_supports_vm(void);
 void kvm__arch_read_term(struct kvm *kvm);
 
+#ifdef ARCH_HAS_CFG_RAM_ADDRESS
+static inline bool kvm__arch_has_cfg_ram_address(void)
+{
+       return true;
+}
+#else
+static inline bool kvm__arch_has_cfg_ram_address(void)
+{
+       return false;
+}
+#endif
+
 void *guest_flat_to_host(struct kvm *kvm, u64 offset);
 u64 host_to_guest_flat(struct kvm *kvm, void *ptr);
 
diff --git a/include/linux/sizes.h b/include/linux/sizes.h
index b2b5c457cf1c..52afca02aa6e 100644
--- a/include/linux/sizes.h
+++ b/include/linux/sizes.h
@@ -44,4 +44,6 @@
 #define SZ_1G                          0x40000000ULL
 #define SZ_2G                          0x80000000ULL
 
+#define SZ_4G                          0x100000000ULL
+
 #endif /* __LINUX_SIZES_H__ */
-- 
2.36.1

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