[PATCH] x86/PVH: replace bogus assertion with conditional

[PATCH] x86/PVH: replace bogus assertion with conditional

[Jan Beulich]

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While PVH guests currently have to start in 64-bit mode, nothing keeps
them from entering compatibility mode via a suitable ring-0 code
selector and making a hypercall from there. Fail such attempts rather
than asserting they won't happen.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4876,10 +4876,10 @@ int hvm_do_hypercall(struct cpu_user_reg
                                                    regs->r8, regs->r9);
         curr->arch.hvm_vcpu.hcall_64bit = 0;
     }
+    else if ( unlikely(is_pvh_vcpu(curr)) )
+        regs->_eax = -ENOSYS; /* PVH 32bitfixme. */
     else
     {
-        ASSERT(!is_pvh_vcpu(curr));   /* PVH 32bitfixme. */
-
         HVM_DBG_LOG(DBG_LEVEL_HCALL, "hcall%u(%x, %x, %x, %x, %x, %x)", eax,
                     (uint32_t)regs->ebx, (uint32_t)regs->ecx,
                     (uint32_t)regs->edx, (uint32_t)regs->esi,




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x86/PVH: replace bogus assertion with conditional

While PVH guests currently have to start in 64-bit mode, nothing keeps
them from entering compatibility mode via a suitable ring-0 code
selector and making a hypercall from there. Fail such attempts rather
than asserting they won't happen.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4876,10 +4876,10 @@ int hvm_do_hypercall(struct cpu_user_reg
                                                    regs->r8, regs->r9);
         curr->arch.hvm_vcpu.hcall_64bit = 0;
     }
+    else if ( unlikely(is_pvh_vcpu(curr)) )
+        regs->_eax = -ENOSYS; /* PVH 32bitfixme. */
     else
     {
-        ASSERT(!is_pvh_vcpu(curr));   /* PVH 32bitfixme. */
-
         HVM_DBG_LOG(DBG_LEVEL_HCALL, "hcall%u(%x, %x, %x, %x, %x, %x)", eax,
                     (uint32_t)regs->ebx, (uint32_t)regs->ecx,
                     (uint32_t)regs->edx, (uint32_t)regs->esi,

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Re: [PATCH] x86/PVH: replace bogus assertion with conditional

[Andrew Cooper]

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On 31/10/14 10:44, Jan Beulich wrote:
> While PVH guests currently have to start in 64-bit mode, nothing keeps
> them from entering compatibility mode via a suitable ring-0 code
> selector and making a hypercall from there. Fail such attempts rather
> than asserting they won't happen.
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

>
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -4876,10 +4876,10 @@ int hvm_do_hypercall(struct cpu_user_reg
>                                                     regs->r8, regs->r9);
>          curr->arch.hvm_vcpu.hcall_64bit = 0;
>      }
> +    else if ( unlikely(is_pvh_vcpu(curr)) )
> +        regs->_eax = -ENOSYS; /* PVH 32bitfixme. */
>      else
>      {
> -        ASSERT(!is_pvh_vcpu(curr));   /* PVH 32bitfixme. */
> -
>          HVM_DBG_LOG(DBG_LEVEL_HCALL, "hcall%u(%x, %x, %x, %x, %x, %x)", eax,
>                      (uint32_t)regs->ebx, (uint32_t)regs->ecx,
>                      (uint32_t)regs->edx, (uint32_t)regs->esi,
>
>
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel


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