[Xen-changelog] [xen stable-4.8] xen/arm: do_trap_hypervisor: Separate hypervisor and guest traps

[patchbot@xxxxxxx]

commit 5026eb5ed010528ae46ca4f654ea0e1c2626a9d9
Author:     Julien Grall <julien.grall@xxxxxxx>
AuthorDate: Fri May 5 15:30:35 2017 +0100
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Mon Jun 12 14:36:06 2017 -0700

    xen/arm: do_trap_hypervisor: Separate hypervisor and guest traps
    
    The function do_trap_hypervisor is currently handling both trap coming
    from the hypervisor and the guest. This makes difficult to get specific
    behavior when a trap is coming from either the guest or the hypervisor.
    
    Split the function into two parts:
        - do_trap_guest_sync to handle guest traps
        - do_trap_hyp_sync to handle hypervisor traps
    
    On AArch32, the Hyp Trap Exception provides the standard mechanism for
    trapping Guest OS functions to the hypervisor (see B1.14.1 in ARM DDI
    0406C.c). It cannot be generated when generated when the processor is in
    Hyp Mode, instead other exception will be used. So it is fine to replace
    the call to do_trap_hypervisor by do_trap_guest_sync.
    
    For AArch64, there are two distincts exception depending whether the
    exception was taken from the current level (hypervisor) or lower level
    (guest).
    
    Note that the unknown traps from guests will lead to panic Xen. This is
    already behavior and is left unchanged for simplicy. A follow-up patch
    will address that.
    
    Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
    Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    master-commit-id: 5a0ed9a09ebb32b620d9217875bb5206d5ccf4d7
---
 xen/arch/arm/arm32/entry.S |  4 ++--
 xen/arch/arm/arm64/entry.S |  6 +++---
 xen/arch/arm/traps.c       | 17 ++++++++++++++++-
 3 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/xen/arch/arm/arm32/entry.S b/xen/arch/arm/arm32/entry.S
index d7cd06c..090f049 100644
--- a/xen/arch/arm/arm32/entry.S
+++ b/xen/arch/arm/arm32/entry.S
@@ -130,7 +130,7 @@ GLOBAL(hyp_traps_vector)
         b trap_supervisor_call          /* 0x08 - Supervisor Call */
         b trap_prefetch_abort           /* 0x0c - Prefetch Abort */
         b trap_data_abort               /* 0x10 - Data Abort */
-        b trap_hypervisor               /* 0x14 - Hypervisor */
+        b trap_guest_sync               /* 0x14 - Hypervisor */
         b trap_irq                      /* 0x18 - IRQ */
         b trap_fiq                      /* 0x1c - FIQ */
 
@@ -138,7 +138,7 @@ DEFINE_TRAP_ENTRY(undefined_instruction)
 DEFINE_TRAP_ENTRY(supervisor_call)
 DEFINE_TRAP_ENTRY(prefetch_abort)
 DEFINE_TRAP_ENTRY(data_abort)
-DEFINE_TRAP_ENTRY(hypervisor)
+DEFINE_TRAP_ENTRY(guest_sync)
 DEFINE_TRAP_ENTRY_NOIRQ(irq)
 DEFINE_TRAP_ENTRY_NOIRQ(fiq)
 
diff --git a/xen/arch/arm/arm64/entry.S b/xen/arch/arm/arm64/entry.S
index 66ba0cb..0e7ddde 100644
--- a/xen/arch/arm/arm64/entry.S
+++ b/xen/arch/arm/arm64/entry.S
@@ -219,7 +219,7 @@ hyp_sync:
         entry   hyp=1
         msr     daifclr, #2
         mov     x0, sp
-        bl      do_trap_hypervisor
+        bl      do_trap_hyp_sync
         exit    hyp=1
 
 hyp_irq:
@@ -238,7 +238,7 @@ guest_sync:
         cbnz    x0, 1f
         msr     daifclr, #2
         mov     x0, sp
-        bl      do_trap_hypervisor
+        bl      do_trap_guest_sync
 1:
         exit    hyp=0, compat=0
 
@@ -276,7 +276,7 @@ guest_sync_compat:
         cbnz    x0, 1f
         msr     daifclr, #2
         mov     x0, sp
-        bl      do_trap_hypervisor
+        bl      do_trap_guest_sync
 1:
         exit    hyp=0, compat=1
 
diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c
index 40805de..518a36e 100644
--- a/xen/arch/arm/traps.c
+++ b/xen/arch/arm/traps.c
@@ -2657,7 +2657,7 @@ static void enter_hypervisor_head(struct cpu_user_regs 
*regs)
         gic_clear_lrs(current);
 }
 
-asmlinkage void do_trap_hypervisor(struct cpu_user_regs *regs)
+asmlinkage void do_trap_guest_sync(struct cpu_user_regs *regs)
 {
     const union hsr hsr = { .bits = regs->hsr };
 
@@ -2777,6 +2777,21 @@ asmlinkage void do_trap_hypervisor(struct cpu_user_regs 
*regs)
         do_trap_data_abort_guest(regs, hsr);
         break;
 
+    default:
+        printk("Unknown Guest Trap. HSR=0x%x EC=0x%x IL=%x 
Syndrome=0x%"PRIx32"\n",
+               hsr.bits, hsr.ec, hsr.len, hsr.iss);
+        do_unexpected_trap("Guest", regs);
+    }
+}
+
+asmlinkage void do_trap_hyp_sync(struct cpu_user_regs *regs)
+{
+    const union hsr hsr = { .bits = regs->hsr };
+
+    enter_hypervisor_head(regs);
+
+    switch ( hsr.ec )
+    {
 #ifdef CONFIG_ARM_64
     case HSR_EC_BRK:
         do_trap_brk(regs, hsr);
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.8

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