[V10 PATCH 08/23] PVH xen: Introduce PVH guest type and some basic changes.

[Mukesh Rathor <mukesh.rathor@oracle.com>]

This patch introduces the concept of a pvh guest. There are other basic
changes like creating macros to check for pv/pvh vcpu/domain, and also
modifying copy-macros to account for pvh. Finally, guest_kernel_mode is
changed to boast that a PVH doesn't need to check for TF_kernel_mode
flag since the kernel runs in ring 0.

Chagnes in V2:
  - make is_pvh/is_hvm enum instead of adding is_pvh as a new flag.
  - fix indentation and spacing in guest_kernel_mode macro.
  - add debug only BUG() in GUEST_KERNEL_RPL macro as it should no longer
    be called in any PVH paths.

Chagnes in V3:
  - Rename enum fields, and add is_pv to it.
  - Get rid if is_hvm_or_pvh_* macros.

Chagnes in V4:
  - Move e820 fields out of pv_domain struct.

Chagnes in V5:
  - Move e820 changes above in V4, to a separate patch.

Chagnes in V5:
  - Rename enum guest_type from is_pv, ... to guest_type_pv, ....

Chagnes in V8:
  - Got to VMCS for DPL check instead of checking the rpl in
    guest_kernel_mode.  Note, we drop the const qualifier from
    vcpu_show_registers() to accomodate the hvm function call in
    guest_kernel_mode().
  - Also, hvm_kernel_mode is put in hvm.c because it's called from
    guest_kernel_mode in regs.h which is a pretty early header include.
    Hence, we can't place it in hvm.h like other similar functions.
    The other alternative, to put hvm_kernel_mode in regs.h itself,
    but then it calls hvm_get_segment_register() for which either we
    need to include hvm.h in regs.h, not possible, or add
    proto for hvm_get_segment_register(). But then the args to
    hvm_get_segment_register() also need their headers. So, in the
    end this seems to be the best/only way.

Signed-off-by: Mukesh Rathor <mukesh.rathor@oracle.com>
---
 xen/arch/x86/debug.c               |    2 +-
 xen/arch/x86/hvm/hvm.c             |    8 ++++++++
 xen/arch/x86/x86_64/traps.c        |    2 +-
 xen/common/domain.c                |    2 +-
 xen/include/asm-x86/desc.h         |    4 +++-
 xen/include/asm-x86/domain.h       |    2 +-
 xen/include/asm-x86/guest_access.h |   12 ++++++------
 xen/include/asm-x86/x86_64/regs.h  |   11 +++++++----
 xen/include/public/domctl.h        |    3 +++
 xen/include/xen/sched.h            |   21 ++++++++++++++++++---
 10 files changed, 49 insertions(+), 18 deletions(-)

diff --git a/xen/arch/x86/debug.c b/xen/arch/x86/debug.c
index e67473e..167421d 100644
--- a/xen/arch/x86/debug.c
+++ b/xen/arch/x86/debug.c
@@ -158,7 +158,7 @@ dbg_rw_guest_mem(dbgva_t addr, dbgbyte_t *buf, int len, struct domain *dp,
 
         pagecnt = min_t(long, PAGE_SIZE - (addr & ~PAGE_MASK), len);
 
-        mfn = (dp->is_hvm
+        mfn = (!is_pv_domain(dp)
                ? dbg_hvm_va2mfn(addr, dp, toaddr, &gfn)
                : dbg_pv_va2mfn(addr, dp, pgd3));
         if ( mfn == INVALID_MFN ) 
diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 8284b3b..bac4708 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4642,6 +4642,14 @@ enum hvm_intblk nhvm_interrupt_blocked(struct vcpu *v)
     return hvm_funcs.nhvm_intr_blocked(v);
 }
 
+bool_t hvm_kernel_mode(struct vcpu *v)
+{
+    struct segment_register seg;
+
+    hvm_get_segment_register(v, x86_seg_ss, &seg);
+    return (seg.attr.fields.dpl == 0);
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/x86/x86_64/traps.c b/xen/arch/x86/x86_64/traps.c
index 9e0571d..feb50ff 100644
--- a/xen/arch/x86/x86_64/traps.c
+++ b/xen/arch/x86/x86_64/traps.c
@@ -141,7 +141,7 @@ void show_registers(struct cpu_user_regs *regs)
     }
 }
 
-void vcpu_show_registers(const struct vcpu *v)
+void vcpu_show_registers(struct vcpu *v)
 {
     const struct cpu_user_regs *regs = &v->arch.user_regs;
     unsigned long crs[8];
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 6c264a5..38b1bad 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -236,7 +236,7 @@ struct domain *domain_create(
         goto fail;
 
     if ( domcr_flags & DOMCRF_hvm )
-        d->is_hvm = 1;
+        d->guest_type = guest_type_hvm;
 
     if ( domid == 0 )
     {
diff --git a/xen/include/asm-x86/desc.h b/xen/include/asm-x86/desc.h
index 354b889..041e9d3 100644
--- a/xen/include/asm-x86/desc.h
+++ b/xen/include/asm-x86/desc.h
@@ -38,7 +38,9 @@
 
 #ifndef __ASSEMBLY__
 
-#define GUEST_KERNEL_RPL(d) (is_pv_32bit_domain(d) ? 1 : 3)
+/* PVH 32bitfixme : see emulate_gate_op call from do_general_protection */
+#define GUEST_KERNEL_RPL(d) ({ ASSERT(is_pv_domain(d)); \
+                               is_pv_32bit_domain(d) ? 1 : 3; })
 
 /* Fix up the RPL of a guest segment selector. */
 #define __fixup_guest_selector(d, sel)                             \
diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
index c3f9f8e..22a72df 100644
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -447,7 +447,7 @@ struct arch_vcpu
 #define hvm_svm         hvm_vcpu.u.svm
 
 void vcpu_show_execution_state(struct vcpu *);
-void vcpu_show_registers(const struct vcpu *);
+void vcpu_show_registers(struct vcpu *);
 
 /* Clean up CR4 bits that are not under guest control. */
 unsigned long pv_guest_cr4_fixup(const struct vcpu *, unsigned long guest_cr4);
diff --git a/xen/include/asm-x86/guest_access.h b/xen/include/asm-x86/guest_access.h
index ca700c9..675dda1 100644
--- a/xen/include/asm-x86/guest_access.h
+++ b/xen/include/asm-x86/guest_access.h
@@ -14,27 +14,27 @@
 
 /* Raw access functions: no type checking. */
 #define raw_copy_to_guest(dst, src, len)        \
-    (is_hvm_vcpu(current) ?                     \
+    (!is_pv_vcpu(current) ?                     \
      copy_to_user_hvm((dst), (src), (len)) :    \
      copy_to_user((dst), (src), (len)))
 #define raw_copy_from_guest(dst, src, len)      \
-    (is_hvm_vcpu(current) ?                     \
+    (!is_pv_vcpu(current) ?                     \
      copy_from_user_hvm((dst), (src), (len)) :  \
      copy_from_user((dst), (src), (len)))
 #define raw_clear_guest(dst,  len)              \
-    (is_hvm_vcpu(current) ?                     \
+    (!is_pv_vcpu(current) ?                     \
      clear_user_hvm((dst), (len)) :             \
      clear_user((dst), (len)))
 #define __raw_copy_to_guest(dst, src, len)      \
-    (is_hvm_vcpu(current) ?                     \
+    (!is_pv_vcpu(current) ?                     \
      copy_to_user_hvm((dst), (src), (len)) :    \
      __copy_to_user((dst), (src), (len)))
 #define __raw_copy_from_guest(dst, src, len)    \
-    (is_hvm_vcpu(current) ?                     \
+    (!is_pv_vcpu(current) ?                     \
      copy_from_user_hvm((dst), (src), (len)) :  \
      __copy_from_user((dst), (src), (len)))
 #define __raw_clear_guest(dst,  len)            \
-    (is_hvm_vcpu(current) ?                     \
+    (!is_pv_vcpu(current) ?                     \
      clear_user_hvm((dst), (len)) :             \
      clear_user((dst), (len)))
 
diff --git a/xen/include/asm-x86/x86_64/regs.h b/xen/include/asm-x86/x86_64/regs.h
index 3cdc702..d91a84b 100644
--- a/xen/include/asm-x86/x86_64/regs.h
+++ b/xen/include/asm-x86/x86_64/regs.h
@@ -10,10 +10,13 @@
 #define ring_2(r)    (((r)->cs & 3) == 2)
 #define ring_3(r)    (((r)->cs & 3) == 3)
 
-#define guest_kernel_mode(v, r)                                 \
-    (!is_pv_32bit_vcpu(v) ?                                     \
-     (ring_3(r) && ((v)->arch.flags & TF_kernel_mode)) :        \
-     (ring_1(r)))
+bool_t hvm_kernel_mode(struct vcpu *);
+
+#define guest_kernel_mode(v, r)                                   \
+    (is_pvh_vcpu(v) ? hvm_kernel_mode(v) :                        \
+     (!is_pv_32bit_vcpu(v) ?                                      \
+      (ring_3(r) && ((v)->arch.flags & TF_kernel_mode)) :         \
+      (ring_1(r))))
 
 #define permit_softint(dpl, v, r) \
     ((dpl) >= (guest_kernel_mode(v, r) ? 1 : 3))
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 4c5b2bb..6b1aa11 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -89,6 +89,9 @@ struct xen_domctl_getdomaininfo {
  /* Being debugged.  */
 #define _XEN_DOMINF_debugged  6
 #define XEN_DOMINF_debugged   (1U<<_XEN_DOMINF_debugged)
+/* domain is PVH */
+#define _XEN_DOMINF_pvh_guest 7
+#define XEN_DOMINF_pvh_guest   (1U<<_XEN_DOMINF_pvh_guest)
  /* XEN_DOMINF_shutdown guest-supplied code.  */
 #define XEN_DOMINF_shutdownmask 255
 #define XEN_DOMINF_shutdownshift 16
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index ae6a3b8..2d48d22 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -238,6 +238,14 @@ struct mem_event_per_domain
     struct mem_event_domain access;
 };
 
+/*
+ * PVH is a PV guest running in an HVM container. While is_hvm_* checks are
+ * false for it, it uses many of the HVM data structs.
+ */
+enum guest_type {
+    guest_type_pv, guest_type_pvh, guest_type_hvm
+};
+
 struct domain
 {
     domid_t          domain_id;
@@ -285,8 +293,8 @@ struct domain
     struct rangeset *iomem_caps;
     struct rangeset *irq_caps;
 
-    /* Is this an HVM guest? */
-    bool_t           is_hvm;
+    enum guest_type guest_type;
+
 #ifdef HAS_PASSTHROUGH
     /* Does this guest need iommu mappings? */
     bool_t           need_iommu;
@@ -464,6 +472,9 @@ struct domain *domain_create(
  /* DOMCRF_oos_off: dont use out-of-sync optimization for shadow page tables */
 #define _DOMCRF_oos_off         4
 #define DOMCRF_oos_off          (1U<<_DOMCRF_oos_off)
+ /* DOMCRF_pvh: Create PV domain in HVM container. */
+#define _DOMCRF_pvh            5
+#define DOMCRF_pvh             (1U<<_DOMCRF_pvh)
 
 /*
  * rcu_lock_domain_by_id() is more efficient than get_domain_by_id().
@@ -732,8 +743,12 @@ void watchdog_domain_destroy(struct domain *d);
 
 #define VM_ASSIST(_d,_t) (test_bit((_t), &(_d)->vm_assist))
 
-#define is_hvm_domain(d) ((d)->is_hvm)
+#define is_pv_domain(d) ((d)->guest_type == guest_type_pv)
+#define is_pv_vcpu(v)   (is_pv_domain((v)->domain))
+#define is_hvm_domain(d) ((d)->guest_type == guest_type_hvm)
 #define is_hvm_vcpu(v)   (is_hvm_domain(v->domain))
+#define is_pvh_domain(d) ((d)->guest_type == guest_type_pvh)
+#define is_pvh_vcpu(v)   (is_pvh_domain((v)->domain))
 #define is_pinned_vcpu(v) ((v)->domain->is_pinned || \
                            cpumask_weight((v)->cpu_affinity) == 1)
 #ifdef HAS_PASSTHROUGH
-- 
1.7.2.3