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Re: [Xen-devel] [PATCH v12 for-xen-4.5 09/20] x86/VPMU: Add public xenpmu.h



On 09/29/2014 11:41 AM, Jan Beulich wrote:
On 29.09.14 at 17:19, <boris.ostrovsky@xxxxxxxxxx> wrote:
On 09/29/2014 10:30 AM, Jan Beulich wrote:
On 29.09.14 at 16:17, <JBeulich@xxxxxxxx> wrote:
On 25.09.14 at 21:28, <boris.ostrovsky@xxxxxxxxxx> wrote:
--- a/xen/include/public/arch-x86/xen-x86_64.h
+++ b/xen/include/public/arch-x86/xen-x86_64.h
@@ -174,6 +174,14 @@ struct cpu_user_regs {
   typedef struct cpu_user_regs cpu_user_regs_t;
   DEFINE_XEN_GUEST_HANDLE(cpu_user_regs_t);
+struct xen_pmu_regs {
+    __DECL_REG(ip);
+    __DECL_REG(sp);
Do you really need __DECL_REG() here? I.e. can't these two fields
be just xen_ulong_t e[is]p and the structure definition then be
shared with 32-bit code (and hence moved altogether into pmu.h)?
Otoh - is cs useful at all on 64-bit?
perf uses user_mode() to figure which mode we are in and that requires CS.
But that won't be complete without also looking at EFLAGS.VM.


True. In perf case, they explicitly state that v8086 mode is ruled out so EFLAGS check can be bypassed. But for completeness I should put EFLAGS in.

-boris

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