[xen stable-4.15] x86/HVM: wire up multicalls

[patchbot@xxxxxxx]

commit 0f1002d40644841295578b2189c1489b0a9276ec
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Jun 24 16:35:39 2021 +0200
Commit:     Ian Jackson <iwj@xxxxxxxxxxxxxx>
CommitDate: Thu Aug 19 17:33:28 2021 +0100

    x86/HVM: wire up multicalls
    
    To be able to use them from, in particular, the tool stack, they need to
    be supported for all guest types. Note that xc_resource_op() already
    does, so would not work without this on PVH Dom0.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Begrudingly acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Ian Jackson <iwj@xxxxxxxxxxxxxx>
    Backport-requested-by: Jan Beulich <jbeulich@xxxxxxxx>
    (cherry picked from commit 198a2bc6f149ca41e16d90fc73de2c81affe4490)
---
 xen/arch/x86/hvm/hypercall.c    | 35 +++++++++++++++++++++++++++++++++++
 xen/arch/x86/hypercall.c        | 14 ++++++++++----
 xen/arch/x86/pv/hypercall.c     |  3 ++-
 xen/include/asm-x86/multicall.h | 12 ++++++++++++
 4 files changed, 59 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/hvm/hypercall.c b/xen/arch/x86/hvm/hypercall.c
index b084afcbce..01846b0718 100644
--- a/xen/arch/x86/hvm/hypercall.c
+++ b/xen/arch/x86/hvm/hypercall.c
@@ -26,6 +26,7 @@
 #include <asm/hvm/emulate.h>
 #include <asm/hvm/support.h>
 #include <asm/hvm/viridian.h>
+#include <asm/multicall.h>
 
 #include <public/hvm/hvm_op.h>
 #include <public/hvm/params.h>
@@ -123,6 +124,7 @@ static long hvm_physdev_op(int cmd, 
XEN_GUEST_HANDLE_PARAM(void) arg)
 
 static const hypercall_table_t hvm_hypercall_table[] = {
     HVM_CALL(memory_op),
+    COMPAT_CALL(multicall),
 #ifdef CONFIG_GRANT_TABLE
     HVM_CALL(grant_table_op),
 #endif
@@ -332,6 +334,39 @@ int hvm_hypercall(struct cpu_user_regs *regs)
     return curr->hcall_preempted ? HVM_HCALL_preempted : HVM_HCALL_completed;
 }
 
+enum mc_disposition hvm_do_multicall_call(struct mc_state *state)
+{
+    struct vcpu *curr = current;
+    hypercall_fn_t *func = NULL;
+
+    if ( hvm_guest_x86_mode(curr) == 8 )
+    {
+        struct multicall_entry *call = &state->call;
+
+        if ( call->op < ARRAY_SIZE(hvm_hypercall_table) )
+            func = array_access_nospec(hvm_hypercall_table, call->op).native;
+        if ( func )
+            call->result = func(call->args[0], call->args[1], call->args[2],
+                                call->args[3], call->args[4], call->args[5]);
+        else
+            call->result = -ENOSYS;
+    }
+    else
+    {
+        struct compat_multicall_entry *call = &state->compat_call;
+
+        if ( call->op < ARRAY_SIZE(hvm_hypercall_table) )
+            func = array_access_nospec(hvm_hypercall_table, call->op).compat;
+        if ( func )
+            call->result = func(call->args[0], call->args[1], call->args[2],
+                                call->args[3], call->args[4], call->args[5]);
+        else
+            call->result = -ENOSYS;
+    }
+
+    return !hvm_get_cpl(curr) ? mc_continue : mc_preempt;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/x86/hypercall.c b/xen/arch/x86/hypercall.c
index 14da9bc4ad..791b4c7585 100644
--- a/xen/arch/x86/hypercall.c
+++ b/xen/arch/x86/hypercall.c
@@ -20,6 +20,7 @@
  */
 
 #include <xen/hypercall.h>
+#include <asm/multicall.h>
 
 #define ARGS(x, n)                              \
     [ __HYPERVISOR_ ## x ] = { n, n }
@@ -264,13 +265,18 @@ int hypercall_xlat_continuation(unsigned int *id, 
unsigned int nr,
     return rc;
 }
 
-#ifndef CONFIG_PV
-/* Stub for arch_do_multicall_call */
-enum mc_disposition arch_do_multicall_call(struct mc_state *mc)
+enum mc_disposition arch_do_multicall_call(struct mc_state *state)
 {
+    const struct domain *currd = current->domain;
+
+    if ( is_pv_domain(currd) )
+        return pv_do_multicall_call(state);
+
+    if ( is_hvm_domain(currd) )
+        return hvm_do_multicall_call(state);
+
     return mc_exit;
 }
-#endif
 
 /*
  * Local variables:
diff --git a/xen/arch/x86/pv/hypercall.c b/xen/arch/x86/pv/hypercall.c
index 20795b4b57..73ccbe05ce 100644
--- a/xen/arch/x86/pv/hypercall.c
+++ b/xen/arch/x86/pv/hypercall.c
@@ -23,6 +23,7 @@
 #include <xen/hypercall.h>
 #include <xen/nospec.h>
 #include <xen/trace.h>
+#include <asm/multicall.h>
 #include <irq_vectors.h>
 
 #define HYPERCALL(x)                                                \
@@ -237,7 +238,7 @@ void pv_hypercall(struct cpu_user_regs *regs)
     perfc_incr(hypercalls);
 }
 
-enum mc_disposition arch_do_multicall_call(struct mc_state *state)
+enum mc_disposition pv_do_multicall_call(struct mc_state *state)
 {
     struct vcpu *curr = current;
     unsigned long op;
diff --git a/xen/include/asm-x86/multicall.h b/xen/include/asm-x86/multicall.h
new file mode 100644
index 0000000000..7e1d4c121a
--- /dev/null
+++ b/xen/include/asm-x86/multicall.h
@@ -0,0 +1,12 @@
+/******************************************************************************
+ * asm-x86/multicall.h
+ */
+
+#ifndef __ASM_X86_MULTICALL_H__
+#define __ASM_X86_MULTICALL_H__
+
+#include <xen/multicall.h>
+
+typeof(arch_do_multicall_call) pv_do_multicall_call, hvm_do_multicall_call;
+
+#endif /* __ASM_X86_MULTICALL_H__ */
--
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