[v4,04/11] xen: harmonize return types of hypercall handlers

Commit Message

Jürgen Groß March 10, 2022, 7:34 a.m. UTC

Today most hypercall handlers have a return type of long, while the
compat ones return an int. There are a few exceptions from that rule,
however.

Get rid of the exceptions by letting compat handlers always return int
and others always return long, with the exception of the Arm specific
physdev_op handler.

For the compat hvm case use eax instead of rax for the stored result as
it should have been from the beginning.

Additionally move some prototypes to include/asm-x86/hypercall.h
as they are x86 specific. Move the compat_platform_op() prototype to
the common header.

Rename paging_domctl_continuation() to do_paging_domctl_cont() and add
a matching define for the associated hypercall.

Make do_callback_op() and compat_callback_op() more similar by adding
the const attribute to compat_callback_op()'s 2nd parameter.

Change the type of the cmd parameter for [do|compat]_kexec_op() to
unsigned int, as this is more appropriate for the compat case.

Signed-off-by: Juergen Gross <[e-mail]>
Reviewed-by: Jan Beulich <[e-mail]>
---
V2:
- rework platform_op compat handling (Jan Beulich)
V3:
- remove include of types.h (Jan Beulich)
V4:
- don't move do_physdev_op() (Julien Grall)
- carve out non style compliant parameter replacements (Julien Grall)
---
 xen/arch/x86/domctl.c                    |  4 +--
 xen/arch/x86/hvm/hypercall.c             |  8 ++----
 xen/arch/x86/hypercall.c                 |  2 +-
 xen/arch/x86/include/asm/hypercall.h     | 31 ++++++++++++------------
 xen/arch/x86/include/asm/paging.h        |  3 ---
 xen/arch/x86/mm/paging.c                 |  3 ++-
 xen/arch/x86/pv/callback.c               | 14 +++++------
 xen/arch/x86/pv/emul-priv-op.c           |  2 +-
 xen/arch/x86/pv/hypercall.c              |  5 +---
 xen/arch/x86/pv/iret.c                   |  4 +--
 xen/arch/x86/pv/misc-hypercalls.c        | 14 +++++++----
 xen/arch/x86/x86_64/platform_hypercall.c |  1 +
 xen/common/argo.c                        |  6 ++---
 xen/common/kexec.c                       |  6 ++---
 xen/include/xen/hypercall.h              | 20 +++++++--------
 15 files changed, 59 insertions(+), 64 deletions(-)

Patch

diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index e49f9e91b9..ea7d60ffb6 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -221,8 +221,8 @@  long arch_do_domctl(
     case XEN_DOMCTL_shadow_op:
         ret = paging_domctl(d, &domctl->u.shadow_op, u_domctl, 0);
         if ( ret == -ERESTART )
-            return hypercall_create_continuation(__HYPERVISOR_arch_1,
-                                                 "h", u_domctl);
+            return hypercall_create_continuation(
+                       __HYPERVISOR_paging_domctl_cont, "h", u_domctl);
         copyback = true;
         break;
 
diff --git a/xen/arch/x86/hvm/hypercall.c b/xen/arch/x86/hvm/hypercall.c
index 030243810e..7ea1afd8fe 100644
--- a/xen/arch/x86/hvm/hypercall.c
+++ b/xen/arch/x86/hvm/hypercall.c
@@ -124,8 +124,6 @@  static long hvm_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
     [ __HYPERVISOR_ ## x ] = { (hypercall_fn_t *) do_ ## x,  \
                                (hypercall_fn_t *) compat_ ## x }
 
-#define do_arch_1             paging_domctl_continuation
-
 static const struct {
     hypercall_fn_t *native, *compat;
 } hvm_hypercall_table[] = {
@@ -158,11 +156,9 @@  static const struct {
 #ifdef CONFIG_HYPFS
     HYPERCALL(hypfs_op),
 #endif
-    HYPERCALL(arch_1)
+    HYPERCALL(paging_domctl_cont)
 };
 
-#undef do_arch_1
-
 #undef HYPERCALL
 #undef HVM_CALL
 #undef COMPAT_CALL
@@ -300,7 +296,7 @@  int hvm_hypercall(struct cpu_user_regs *regs)
 #endif
 
         curr->hcall_compat = true;
-        regs->rax = hvm_hypercall_table[eax].compat(ebx, ecx, edx, esi, edi);
+        regs->eax = hvm_hypercall_table[eax].compat(ebx, ecx, edx, esi, edi);
         curr->hcall_compat = false;
 
 #ifndef NDEBUG
diff --git a/xen/arch/x86/hypercall.c b/xen/arch/x86/hypercall.c
index 2370d31d3f..07e1a45ef5 100644
--- a/xen/arch/x86/hypercall.c
+++ b/xen/arch/x86/hypercall.c
@@ -75,7 +75,7 @@  const hypercall_args_t hypercall_args_table[NR_hypercalls] =
     ARGS(dm_op, 3),
     ARGS(hypfs_op, 5),
     ARGS(mca, 1),
-    ARGS(arch_1, 1),
+    ARGS(paging_domctl_cont, 1),
 };
 
 #undef COMP
diff --git a/xen/arch/x86/include/asm/hypercall.h b/xen/arch/x86/include/asm/hypercall.h
index d6daa7e4cb..49973820af 100644
--- a/xen/arch/x86/include/asm/hypercall.h
+++ b/xen/arch/x86/include/asm/hypercall.h
@@ -11,6 +11,8 @@ 
 #include <public/arch-x86/xen-mca.h> /* for do_mca */
 #include <asm/paging.h>
 
+#define __HYPERVISOR_paging_domctl_cont __HYPERVISOR_arch_1
+
 typedef unsigned long hypercall_fn_t(
     unsigned long, unsigned long, unsigned long,
     unsigned long, unsigned long);
@@ -80,7 +82,7 @@  do_set_debugreg(
     int reg,
     unsigned long value);
 
-extern unsigned long cf_check
+extern long cf_check
 do_get_debugreg(
     int reg);
 
@@ -118,7 +120,7 @@  do_mmuext_op(
 extern long cf_check do_callback_op(
     int cmd, XEN_GUEST_HANDLE_PARAM(const_void) arg);
 
-extern unsigned long cf_check
+extern long cf_check
 do_iret(
     void);
 
@@ -133,17 +135,20 @@  do_set_segment_base(
     unsigned int which,
     unsigned long base);
 
+long cf_check do_nmi_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) arg);
+
+long cf_check do_xenpmu_op(unsigned int op,
+                           XEN_GUEST_HANDLE_PARAM(xen_pmu_params_t) arg);
+
+long cf_check do_paging_domctl_cont(
+    XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl);
+
 #ifdef CONFIG_COMPAT
 
 #include <compat/arch-x86/xen.h>
 #include <compat/physdev.h>
 #include <compat/platform.h>
 
-extern int cf_check
-compat_physdev_op(
-    int cmd,
-    XEN_GUEST_HANDLE_PARAM(void) arg);
-
 extern int
 compat_common_vcpu_op(
     int cmd, struct vcpu *v, XEN_GUEST_HANDLE_PARAM(void) arg);
@@ -154,12 +159,8 @@  extern int cf_check compat_mmuext_op(
     XEN_GUEST_HANDLE_PARAM(uint) pdone,
     unsigned int foreigndom);
 
-DEFINE_XEN_GUEST_HANDLE(compat_platform_op_t);
-extern int cf_check compat_platform_op(
-    XEN_GUEST_HANDLE_PARAM(compat_platform_op_t) u_xenpf_op);
-
-extern long cf_check compat_callback_op(
-    int cmd, XEN_GUEST_HANDLE(void) arg);
+extern int cf_check compat_callback_op(
+    int cmd, XEN_GUEST_HANDLE(const_void) arg);
 
 extern int cf_check compat_update_va_mapping(
     unsigned int va, uint32_t lo, uint32_t hi, unsigned int flags);
@@ -177,12 +178,12 @@  extern int cf_check compat_set_gdt(
 extern int cf_check compat_update_descriptor(
     uint32_t pa_lo, uint32_t pa_hi, uint32_t desc_lo, uint32_t desc_hi);
 
-extern unsigned int cf_check compat_iret(void);
+extern int cf_check compat_iret(void);
 
 extern int cf_check compat_nmi_op(
     unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) arg);
 
-extern long cf_check compat_set_callbacks(
+extern int cf_check compat_set_callbacks(
     unsigned long event_selector, unsigned long event_address,
     unsigned long failsafe_selector, unsigned long failsafe_address);
 
diff --git a/xen/arch/x86/include/asm/paging.h b/xen/arch/x86/include/asm/paging.h
index f0b4efc66e..54c440be65 100644
--- a/xen/arch/x86/include/asm/paging.h
+++ b/xen/arch/x86/include/asm/paging.h
@@ -234,9 +234,6 @@  int paging_domctl(struct domain *d, struct xen_domctl_shadow_op *sc,
                   XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl,
                   bool_t resuming);
 
-/* Helper hypercall for dealing with continuations. */
-long cf_check paging_domctl_continuation(XEN_GUEST_HANDLE_PARAM(xen_domctl_t));
-
 /* Call when destroying a vcpu/domain */
 void paging_vcpu_teardown(struct vcpu *v);
 int paging_teardown(struct domain *d);
diff --git a/xen/arch/x86/mm/paging.c b/xen/arch/x86/mm/paging.c
index 1f0b94ad21..a7e2707ecc 100644
--- a/xen/arch/x86/mm/paging.c
+++ b/xen/arch/x86/mm/paging.c
@@ -21,6 +21,7 @@ 
 
 #include <xen/init.h>
 #include <xen/guest_access.h>
+#include <xen/hypercall.h>
 #include <asm/paging.h>
 #include <asm/shadow.h>
 #include <asm/p2m.h>
@@ -759,7 +760,7 @@  int paging_domctl(struct domain *d, struct xen_domctl_shadow_op *sc,
         return shadow_domctl(d, sc, u_domctl);
 }
 
-long cf_check paging_domctl_continuation(
+long cf_check do_paging_domctl_cont(
     XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl)
 {
     struct xen_domctl op;
diff --git a/xen/arch/x86/pv/callback.c b/xen/arch/x86/pv/callback.c
index 55148c7f9e..1be9d3f731 100644
--- a/xen/arch/x86/pv/callback.c
+++ b/xen/arch/x86/pv/callback.c
@@ -207,9 +207,9 @@  long cf_check do_set_callbacks(
 #include <compat/callback.h>
 #include <compat/nmi.h>
 
-static long compat_register_guest_callback(struct compat_callback_register *reg)
+static int compat_register_guest_callback(struct compat_callback_register *reg)
 {
-    long ret = 0;
+    int ret = 0;
     struct vcpu *curr = current;
 
     fixup_guest_code_selector(curr->domain, reg->address.cs);
@@ -256,10 +256,10 @@  static long compat_register_guest_callback(struct compat_callback_register *reg)
     return ret;
 }
 
-static long compat_unregister_guest_callback(
+static int compat_unregister_guest_callback(
     struct compat_callback_unregister *unreg)
 {
-    long ret;
+    int ret;
 
     switch ( unreg->type )
     {
@@ -283,9 +283,9 @@  static long compat_unregister_guest_callback(
     return ret;
 }
 
-long cf_check compat_callback_op(int cmd, XEN_GUEST_HANDLE(void) arg)
+int cf_check compat_callback_op(int cmd, XEN_GUEST_HANDLE(const_void) arg)
 {
-    long ret;
+    int ret;
 
     switch ( cmd )
     {
@@ -321,7 +321,7 @@  long cf_check compat_callback_op(int cmd, XEN_GUEST_HANDLE(void) arg)
     return ret;
 }
 
-long cf_check compat_set_callbacks(
+int cf_check compat_set_callbacks(
     unsigned long event_selector, unsigned long event_address,
     unsigned long failsafe_selector, unsigned long failsafe_address)
 {
diff --git a/xen/arch/x86/pv/emul-priv-op.c b/xen/arch/x86/pv/emul-priv-op.c
index 22b10dec2a..5da00e24e4 100644
--- a/xen/arch/x86/pv/emul-priv-op.c
+++ b/xen/arch/x86/pv/emul-priv-op.c
@@ -22,13 +22,13 @@ 
 #include <xen/domain_page.h>
 #include <xen/event.h>
 #include <xen/guest_access.h>
+#include <xen/hypercall.h>
 #include <xen/iocap.h>
 
 #include <asm/amd.h>
 #include <asm/debugreg.h>
 #include <asm/endbr.h>
 #include <asm/hpet.h>
-#include <asm/hypercall.h>
 #include <asm/mc146818rtc.h>
 #include <asm/pv/domain.h>
 #include <asm/pv/trace.h>
diff --git a/xen/arch/x86/pv/hypercall.c b/xen/arch/x86/pv/hypercall.c
index e8fbee7bbb..fe8dfe9e8f 100644
--- a/xen/arch/x86/pv/hypercall.c
+++ b/xen/arch/x86/pv/hypercall.c
@@ -47,8 +47,6 @@  typedef struct {
 #define COMPAT_CALL(x) HYPERCALL(x)
 #endif
 
-#define do_arch_1             paging_domctl_continuation
-
 static const pv_hypercall_table_t pv_hypercall_table[] = {
     COMPAT_CALL(set_trap_table),
     HYPERCALL(mmu_update),
@@ -109,11 +107,10 @@  static const pv_hypercall_table_t pv_hypercall_table[] = {
 #endif
     HYPERCALL(mca),
 #ifndef CONFIG_PV_SHIM_EXCLUSIVE
-    HYPERCALL(arch_1),
+    HYPERCALL(paging_domctl_cont),
 #endif
 };
 
-#undef do_arch_1
 #undef COMPAT_CALL
 #undef HYPERCALL
 
diff --git a/xen/arch/x86/pv/iret.c b/xen/arch/x86/pv/iret.c
index dd2965d8f0..55eb6a63bd 100644
--- a/xen/arch/x86/pv/iret.c
+++ b/xen/arch/x86/pv/iret.c
@@ -48,7 +48,7 @@  static void async_exception_cleanup(struct vcpu *curr)
         curr->arch.async_exception_state(trap).old_mask;
 }
 
-unsigned long cf_check do_iret(void)
+long cf_check do_iret(void)
 {
     struct cpu_user_regs *regs = guest_cpu_user_regs();
     struct iret_context iret_saved;
@@ -105,7 +105,7 @@  unsigned long cf_check do_iret(void)
 }
 
 #ifdef CONFIG_PV32
-unsigned int cf_check compat_iret(void)
+int cf_check compat_iret(void)
 {
     struct cpu_user_regs *regs = guest_cpu_user_regs();
     struct vcpu *v = current;
diff --git a/xen/arch/x86/pv/misc-hypercalls.c b/xen/arch/x86/pv/misc-hypercalls.c
index 5649aaab44..635f5a644a 100644
--- a/xen/arch/x86/pv/misc-hypercalls.c
+++ b/xen/arch/x86/pv/misc-hypercalls.c
@@ -28,12 +28,16 @@  long cf_check do_set_debugreg(int reg, unsigned long value)
     return set_debugreg(current, reg, value);
 }
 
-unsigned long cf_check do_get_debugreg(int reg)
+long cf_check do_get_debugreg(int reg)
 {
-    unsigned long val;
-    int res = x86emul_read_dr(reg, &val, NULL);
-
-    return res == X86EMUL_OKAY ? val : -ENODEV;
+    /* Avoid implementation defined behavior casting unsigned long to long. */
+    union {
+        unsigned long val;
+        long ret;
+    } u;
+    int res = x86emul_read_dr(reg, &u.val, NULL);
+
+    return res == X86EMUL_OKAY ? u.ret : -ENODEV;
 }
 
 long cf_check do_fpu_taskswitch(int set)
diff --git a/xen/arch/x86/x86_64/platform_hypercall.c b/xen/arch/x86/x86_64/platform_hypercall.c
index 966fd27b5f..2c21a3fd05 100644
--- a/xen/arch/x86/x86_64/platform_hypercall.c
+++ b/xen/arch/x86/x86_64/platform_hypercall.c
@@ -4,6 +4,7 @@ 
 
 EMIT_FILE;
 
+#include <xen/hypercall.h>
 #include <xen/lib.h>
 #include <compat/platform.h>
 #include <xen/hypercall.h>
diff --git a/xen/common/argo.c b/xen/common/argo.c
index 297f6d11f0..26a01c2188 100644
--- a/xen/common/argo.c
+++ b/xen/common/argo.c
@@ -2207,13 +2207,13 @@  do_argo_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) arg1,
 }
 
 #ifdef CONFIG_COMPAT
-long cf_check
+int cf_check
 compat_argo_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) arg1,
                XEN_GUEST_HANDLE_PARAM(void) arg2, unsigned long arg3,
                unsigned long arg4)
 {
     struct domain *currd = current->domain;
-    long rc;
+    int rc;
     xen_argo_send_addr_t send_addr;
     xen_argo_iov_t iovs[XEN_ARGO_MAXIOV];
     compat_argo_iov_t compat_iovs[XEN_ARGO_MAXIOV];
@@ -2267,7 +2267,7 @@  compat_argo_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) arg1,
 
     rc = sendv(currd, &send_addr.src, &send_addr.dst, iovs, niov, arg4);
  out:
-    argo_dprintk("<-compat_argo_op(%u)=%ld\n", cmd, rc);
+    argo_dprintk("<-compat_argo_op(%u)=%d\n", cmd, rc);
 
     return rc;
 }
diff --git a/xen/common/kexec.c b/xen/common/kexec.c
index a2ffb6530c..41669964d2 100644
--- a/xen/common/kexec.c
+++ b/xen/common/kexec.c
@@ -1213,7 +1213,7 @@  static int kexec_status(XEN_GUEST_HANDLE_PARAM(void) uarg)
     return !!test_bit(bit, &kexec_flags);
 }
 
-static int do_kexec_op_internal(unsigned long op,
+static int do_kexec_op_internal(unsigned int op,
                                 XEN_GUEST_HANDLE_PARAM(void) uarg,
                                 bool_t compat)
 {
@@ -1265,13 +1265,13 @@  static int do_kexec_op_internal(unsigned long op,
     return ret;
 }
 
-long cf_check do_kexec_op(unsigned long op, XEN_GUEST_HANDLE_PARAM(void) uarg)
+long cf_check do_kexec_op(unsigned int op, XEN_GUEST_HANDLE_PARAM(void) uarg)
 {
     return do_kexec_op_internal(op, uarg, 0);
 }
 
 #ifdef CONFIG_COMPAT
-int cf_check compat_kexec_op(unsigned long op, XEN_GUEST_HANDLE_PARAM(void) uarg)
+int cf_check compat_kexec_op(unsigned int op, XEN_GUEST_HANDLE_PARAM(void) uarg)
 {
     return do_kexec_op_internal(op, uarg, 1);
 }
diff --git a/xen/include/xen/hypercall.h b/xen/include/xen/hypercall.h
index 81aae7a662..a032ba2b4a 100644
--- a/xen/include/xen/hypercall.h
+++ b/xen/include/xen/hypercall.h
@@ -114,11 +114,6 @@  common_vcpu_op(int cmd,
     struct vcpu *v,
     XEN_GUEST_HANDLE_PARAM(void) arg);
 
-extern long cf_check
-do_nmi_op(
-    unsigned int cmd,
-    XEN_GUEST_HANDLE_PARAM(void) arg);
-
 extern long cf_check
 do_hvm_op(
     unsigned long op,
@@ -126,7 +121,7 @@  do_hvm_op(
 
 extern long cf_check
 do_kexec_op(
-    unsigned long op,
+    unsigned int op,
     XEN_GUEST_HANDLE_PARAM(void) uarg);
 
 extern long cf_check
@@ -145,9 +140,6 @@  extern long cf_check do_argo_op(
 extern long cf_check
 do_xenoprof_op(int op, XEN_GUEST_HANDLE_PARAM(void) arg);
 
-extern long cf_check
-do_xenpmu_op(unsigned int op, XEN_GUEST_HANDLE_PARAM(xen_pmu_params_t) arg);
-
 extern long cf_check
 do_dm_op(
     domid_t domid,
@@ -205,15 +197,21 @@  extern int cf_check compat_xsm_op(
     XEN_GUEST_HANDLE_PARAM(void) op);
 
 extern int cf_check compat_kexec_op(
-    unsigned long op, XEN_GUEST_HANDLE_PARAM(void) uarg);
+    unsigned int op, XEN_GUEST_HANDLE_PARAM(void) uarg);
 
 DEFINE_XEN_GUEST_HANDLE(multicall_entry_compat_t);
 extern int cf_check compat_multicall(
     XEN_GUEST_HANDLE_PARAM(multicall_entry_compat_t) call_list,
     uint32_t nr_calls);
 
+int compat_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg);
+
+typedef struct compat_platform_op compat_platform_op_t;
+DEFINE_XEN_GUEST_HANDLE(compat_platform_op_t);
+int compat_platform_op(XEN_GUEST_HANDLE_PARAM(compat_platform_op_t) u_xenpf_op);
+
 #ifdef CONFIG_ARGO
-extern long cf_check compat_argo_op(
+extern int cf_check compat_argo_op(
     unsigned int cmd,
     XEN_GUEST_HANDLE_PARAM(void) arg1,
     XEN_GUEST_HANDLE_PARAM(void) arg2,