Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 349 insertions, 0 deletions

diff --git a/linux-user/qemu.h b/linux-user/qemu.h
new file mode 100644
index 000000000..5c713fa8a
--- /dev/null
+++ b/linux-user/qemu.h
@@ -0,0 +1,349 @@
+#ifndef QEMU_H
+#define QEMU_H
+
+#include "cpu.h"
+#include "exec/cpu_ldst.h"
+
+#undef DEBUG_REMAP
+
+#include "exec/user/abitypes.h"
+
+#include "syscall_defs.h"
+#include "target_syscall.h"
+
+/*
+ * This is the size of the host kernel's sigset_t, needed where we make
+ * direct system calls that take a sigset_t pointer and a size.
+ */
+#define SIGSET_T_SIZE (_NSIG / 8)
+
+/*
+ * This struct is used to hold certain information about the image.
+ * Basically, it replicates in user space what would be certain
+ * task_struct fields in the kernel
+ */
+struct image_info {
+        abi_ulong       load_bias;
+        abi_ulong       load_addr;
+        abi_ulong       start_code;
+        abi_ulong       end_code;
+        abi_ulong       start_data;
+        abi_ulong       end_data;
+        abi_ulong       start_brk;
+        abi_ulong       brk;
+        abi_ulong       reserve_brk;
+        abi_ulong       start_mmap;
+        abi_ulong       start_stack;
+        abi_ulong       stack_limit;
+        abi_ulong       entry;
+        abi_ulong       code_offset;
+        abi_ulong       data_offset;
+        abi_ulong       saved_auxv;
+        abi_ulong       auxv_len;
+        abi_ulong       arg_start;
+        abi_ulong       arg_end;
+        abi_ulong       arg_strings;
+        abi_ulong       env_strings;
+        abi_ulong       file_string;
+        uint32_t        elf_flags;
+        int             personality;
+        abi_ulong       alignment;
+
+        /* The fields below are used in FDPIC mode.  */
+        abi_ulong       loadmap_addr;
+        uint16_t        nsegs;
+        void            *loadsegs;
+        abi_ulong       pt_dynamic_addr;
+        abi_ulong       interpreter_loadmap_addr;
+        abi_ulong       interpreter_pt_dynamic_addr;
+        struct image_info *other_info;
+
+        /* For target-specific processing of NT_GNU_PROPERTY_TYPE_0. */
+        uint32_t        note_flags;
+
+#ifdef TARGET_MIPS
+        int             fp_abi;
+        int             interp_fp_abi;
+#endif
+};
+
+#ifdef TARGET_I386
+/* Information about the current linux thread */
+struct vm86_saved_state {
+    uint32_t eax; /* return code */
+    uint32_t ebx;
+    uint32_t ecx;
+    uint32_t edx;
+    uint32_t esi;
+    uint32_t edi;
+    uint32_t ebp;
+    uint32_t esp;
+    uint32_t eflags;
+    uint32_t eip;
+    uint16_t cs, ss, ds, es, fs, gs;
+};
+#endif
+
+#if defined(TARGET_ARM) && defined(TARGET_ABI32)
+/* FPU emulator */
+#include "nwfpe/fpa11.h"
+#endif
+
+#define MAX_SIGQUEUE_SIZE 1024
+
+struct emulated_sigtable {
+    int pending; /* true if signal is pending */
+    target_siginfo_t info;
+};
+
+/*
+ * NOTE: we force a big alignment so that the stack stored after is
+ * aligned too
+ */
+typedef struct TaskState {
+    pid_t ts_tid;     /* tid (or pid) of this task */
+#ifdef TARGET_ARM
+# ifdef TARGET_ABI32
+    /* FPA state */
+    FPA11 fpa;
+# endif
+#endif
+#if defined(TARGET_ARM) || defined(TARGET_RISCV)
+    int swi_errno;
+#endif
+#if defined(TARGET_I386) && !defined(TARGET_X86_64)
+    abi_ulong target_v86;
+    struct vm86_saved_state vm86_saved_regs;
+    struct target_vm86plus_struct vm86plus;
+    uint32_t v86flags;
+    uint32_t v86mask;
+#endif
+    abi_ulong child_tidptr;
+#ifdef TARGET_M68K
+    abi_ulong tp_value;
+#endif
+#if defined(TARGET_ARM) || defined(TARGET_M68K) || defined(TARGET_RISCV)
+    /* Extra fields for semihosted binaries.  */
+    abi_ulong heap_base;
+    abi_ulong heap_limit;
+#endif
+    abi_ulong stack_base;
+    int used; /* non zero if used */
+    struct image_info *info;
+    struct linux_binprm *bprm;
+
+    struct emulated_sigtable sync_signal;
+    struct emulated_sigtable sigtab[TARGET_NSIG];
+    /*
+     * This thread's signal mask, as requested by the guest program.
+     * The actual signal mask of this thread may differ:
+     *  + we don't let SIGSEGV and SIGBUS be blocked while running guest code
+     *  + sometimes we block all signals to avoid races
+     */
+    sigset_t signal_mask;
+    /*
+     * The signal mask imposed by a guest sigsuspend syscall, if we are
+     * currently in the middle of such a syscall
+     */
+    sigset_t sigsuspend_mask;
+    /* Nonzero if we're leaving a sigsuspend and sigsuspend_mask is valid. */
+    int in_sigsuspend;
+
+    /*
+     * Nonzero if process_pending_signals() needs to do something (either
+     * handle a pending signal or unblock signals).
+     * This flag is written from a signal handler so should be accessed via
+     * the qatomic_read() and qatomic_set() functions. (It is not accessed
+     * from multiple threads.)
+     */
+    int signal_pending;
+
+    /* This thread's sigaltstack, if it has one */
+    struct target_sigaltstack sigaltstack_used;
+} __attribute__((aligned(16))) TaskState;
+
+abi_long do_brk(abi_ulong new_brk);
+
+/* user access */
+
+#define VERIFY_READ  PAGE_READ
+#define VERIFY_WRITE (PAGE_READ | PAGE_WRITE)
+
+static inline bool access_ok_untagged(int type, abi_ulong addr, abi_ulong size)
+{
+    if (size == 0
+        ? !guest_addr_valid_untagged(addr)
+        : !guest_range_valid_untagged(addr, size)) {
+        return false;
+    }
+    return page_check_range((target_ulong)addr, size, type) == 0;
+}
+
+static inline bool access_ok(CPUState *cpu, int type,
+                             abi_ulong addr, abi_ulong size)
+{
+    return access_ok_untagged(type, cpu_untagged_addr(cpu, addr), size);
+}
+
+/* NOTE __get_user and __put_user use host pointers and don't check access.
+   These are usually used to access struct data members once the struct has
+   been locked - usually with lock_user_struct.  */
+
+/*
+ * Tricky points:
+ * - Use __builtin_choose_expr to avoid type promotion from ?:,
+ * - Invalid sizes result in a compile time error stemming from
+ *   the fact that abort has no parameters.
+ * - It's easier to use the endian-specific unaligned load/store
+ *   functions than host-endian unaligned load/store plus tswapN.
+ * - The pragmas are necessary only to silence a clang false-positive
+ *   warning: see https://bugs.llvm.org/show_bug.cgi?id=39113 .
+ * - gcc has bugs in its _Pragma() support in some versions, eg
+ *   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83256 -- so we only
+ *   include the warning-suppression pragmas for clang
+ */
+#if defined(__clang__) && __has_warning("-Waddress-of-packed-member")
+#define PRAGMA_DISABLE_PACKED_WARNING                                   \
+    _Pragma("GCC diagnostic push");                                     \
+    _Pragma("GCC diagnostic ignored \"-Waddress-of-packed-member\"")
+
+#define PRAGMA_REENABLE_PACKED_WARNING          \
+    _Pragma("GCC diagnostic pop")
+
+#else
+#define PRAGMA_DISABLE_PACKED_WARNING
+#define PRAGMA_REENABLE_PACKED_WARNING
+#endif
+
+#define __put_user_e(x, hptr, e)                                            \
+    do {                                                                    \
+        PRAGMA_DISABLE_PACKED_WARNING;                                      \
+        (__builtin_choose_expr(sizeof(*(hptr)) == 1, stb_p,                 \
+        __builtin_choose_expr(sizeof(*(hptr)) == 2, stw_##e##_p,            \
+        __builtin_choose_expr(sizeof(*(hptr)) == 4, stl_##e##_p,            \
+        __builtin_choose_expr(sizeof(*(hptr)) == 8, stq_##e##_p, abort))))  \
+            ((hptr), (x)), (void)0);                                        \
+        PRAGMA_REENABLE_PACKED_WARNING;                                     \
+    } while (0)
+
+#define __get_user_e(x, hptr, e)                                            \
+    do {                                                                    \
+        PRAGMA_DISABLE_PACKED_WARNING;                                      \
+        ((x) = (typeof(*hptr))(                                             \
+        __builtin_choose_expr(sizeof(*(hptr)) == 1, ldub_p,                 \
+        __builtin_choose_expr(sizeof(*(hptr)) == 2, lduw_##e##_p,           \
+        __builtin_choose_expr(sizeof(*(hptr)) == 4, ldl_##e##_p,            \
+        __builtin_choose_expr(sizeof(*(hptr)) == 8, ldq_##e##_p, abort))))  \
+            (hptr)), (void)0);                                              \
+        PRAGMA_REENABLE_PACKED_WARNING;                                     \
+    } while (0)
+
+
+#ifdef TARGET_WORDS_BIGENDIAN
+# define __put_user(x, hptr)  __put_user_e(x, hptr, be)
+# define __get_user(x, hptr)  __get_user_e(x, hptr, be)
+#else
+# define __put_user(x, hptr)  __put_user_e(x, hptr, le)
+# define __get_user(x, hptr)  __get_user_e(x, hptr, le)
+#endif
+
+/* put_user()/get_user() take a guest address and check access */
+/* These are usually used to access an atomic data type, such as an int,
+ * that has been passed by address.  These internally perform locking
+ * and unlocking on the data type.
+ */
+#define put_user(x, gaddr, target_type)					\
+({									\
+    abi_ulong __gaddr = (gaddr);					\
+    target_type *__hptr;						\
+    abi_long __ret = 0;							\
+    if ((__hptr = lock_user(VERIFY_WRITE, __gaddr, sizeof(target_type), 0))) { \
+        __put_user((x), __hptr);				\
+        unlock_user(__hptr, __gaddr, sizeof(target_type));		\
+    } else								\
+        __ret = -TARGET_EFAULT;						\
+    __ret;								\
+})
+
+#define get_user(x, gaddr, target_type)					\
+({									\
+    abi_ulong __gaddr = (gaddr);					\
+    target_type *__hptr;						\
+    abi_long __ret = 0;							\
+    if ((__hptr = lock_user(VERIFY_READ, __gaddr, sizeof(target_type), 1))) { \
+        __get_user((x), __hptr);				\
+        unlock_user(__hptr, __gaddr, 0);				\
+    } else {								\
+        /* avoid warning */						\
+        (x) = 0;							\
+        __ret = -TARGET_EFAULT;						\
+    }									\
+    __ret;								\
+})
+
+#define put_user_ual(x, gaddr) put_user((x), (gaddr), abi_ulong)
+#define put_user_sal(x, gaddr) put_user((x), (gaddr), abi_long)
+#define put_user_u64(x, gaddr) put_user((x), (gaddr), uint64_t)
+#define put_user_s64(x, gaddr) put_user((x), (gaddr), int64_t)
+#define put_user_u32(x, gaddr) put_user((x), (gaddr), uint32_t)
+#define put_user_s32(x, gaddr) put_user((x), (gaddr), int32_t)
+#define put_user_u16(x, gaddr) put_user((x), (gaddr), uint16_t)
+#define put_user_s16(x, gaddr) put_user((x), (gaddr), int16_t)
+#define put_user_u8(x, gaddr)  put_user((x), (gaddr), uint8_t)
+#define put_user_s8(x, gaddr)  put_user((x), (gaddr), int8_t)
+
+#define get_user_ual(x, gaddr) get_user((x), (gaddr), abi_ulong)
+#define get_user_sal(x, gaddr) get_user((x), (gaddr), abi_long)
+#define get_user_u64(x, gaddr) get_user((x), (gaddr), uint64_t)
+#define get_user_s64(x, gaddr) get_user((x), (gaddr), int64_t)
+#define get_user_u32(x, gaddr) get_user((x), (gaddr), uint32_t)
+#define get_user_s32(x, gaddr) get_user((x), (gaddr), int32_t)
+#define get_user_u16(x, gaddr) get_user((x), (gaddr), uint16_t)
+#define get_user_s16(x, gaddr) get_user((x), (gaddr), int16_t)
+#define get_user_u8(x, gaddr)  get_user((x), (gaddr), uint8_t)
+#define get_user_s8(x, gaddr)  get_user((x), (gaddr), int8_t)
+
+/* copy_from_user() and copy_to_user() are usually used to copy data
+ * buffers between the target and host.  These internally perform
+ * locking/unlocking of the memory.
+ */
+int copy_from_user(void *hptr, abi_ulong gaddr, ssize_t len);
+int copy_to_user(abi_ulong gaddr, void *hptr, ssize_t len);
+
+/* Functions for accessing guest memory.  The tget and tput functions
+   read/write single values, byteswapping as necessary.  The lock_user function
+   gets a pointer to a contiguous area of guest memory, but does not perform
+   any byteswapping.  lock_user may return either a pointer to the guest
+   memory, or a temporary buffer.  */
+
+/* Lock an area of guest memory into the host.  If copy is true then the
+   host area will have the same contents as the guest.  */
+void *lock_user(int type, abi_ulong guest_addr, ssize_t len, bool copy);
+
+/* Unlock an area of guest memory.  The first LEN bytes must be
+   flushed back to guest memory. host_ptr = NULL is explicitly
+   allowed and does nothing. */
+#ifndef DEBUG_REMAP
+static inline void unlock_user(void *host_ptr, abi_ulong guest_addr,
+                               ssize_t len)
+{
+    /* no-op */
+}
+#else
+void unlock_user(void *host_ptr, abi_ulong guest_addr, ssize_t len);
+#endif
+
+/* Return the length of a string in target memory or -TARGET_EFAULT if
+   access error. */
+ssize_t target_strlen(abi_ulong gaddr);
+
+/* Like lock_user but for null terminated strings.  */
+void *lock_user_string(abi_ulong guest_addr);
+
+/* Helper macros for locking/unlocking a target struct.  */
+#define lock_user_struct(type, host_ptr, guest_addr, copy)	\
+    (host_ptr = lock_user(type, guest_addr, sizeof(*host_ptr), copy))
+#define unlock_user_struct(host_ptr, guest_addr, copy)		\
+    unlock_user(host_ptr, guest_addr, (copy) ? sizeof(*host_ptr) : 0)
+
+#endif /* QEMU_H */