[PATCH RFC v2] pvh: clearly specify used parameters in vcpu_guest_context

[Roger Pau Monne <roger.pau@citrix.com>]

The aim of this patch is to define a stable way in which PVH is
going to do AP bringup.

Since we are running inside of a HVM container, PVH should only need
to set flags, cr3 and user_regs in order to bring up a vCPU, the rest
can be set once the vCPU is started using the bare metal methods.
Additionally, the guest can also set cr0 and cr4, and those values
will be appended to the default values set by Xen.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: George Dunlap <george.dunlap@eu.citrix.com>
Cc: Mukesh Rathor <mukesh.rathor@oracle.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Tim Deegan <tim@xen.org>
Cc: Keir Fraser <keir@xen.org>
---
 xen/arch/x86/domain.c             |   24 ++++++++++++++++--------
 xen/arch/x86/hvm/vmx/vmx.c        |    6 +-----
 xen/include/asm-x86/hvm/hvm.h     |    6 +++---
 xen/include/public/arch-x86/xen.h |    8 ++++----
 4 files changed, 24 insertions(+), 20 deletions(-)

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index a3868f9..51311fc 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -51,6 +51,7 @@
 #include <asm/fixmap.h>
 #include <asm/hvm/hvm.h>
 #include <asm/hvm/support.h>
+#include <asm/hvm/nestedhvm.h>
 #include <asm/debugreg.h>
 #include <asm/msr.h>
 #include <asm/traps.h>
@@ -704,9 +705,13 @@ int arch_set_info_guest(
         /* PVH 32bitfixme */
         ASSERT(!compat);
 
-        if ( c(ctrlreg[1]) || c(ldt_base) || c(ldt_ents) ||
+        if ( (c(ctrlreg[0]) & HVM_CR0_GUEST_RESERVED_BITS) ||
+             (c(ctrlreg[4]) & HVM_CR4_GUEST_RESERVED_BITS(v)) ||
+             c(ctrlreg[1]) || c(ctrlreg[2]) || c(ctrlreg[5]) ||
+             c(ctrlreg[6]) || c(ctrlreg[7]) || c(ldt_base) || c(ldt_ents) ||
              c(user_regs.cs) || c(user_regs.ss) || c(user_regs.es) ||
              c(user_regs.ds) || c(user_regs.fs) || c(user_regs.gs) ||
+             c(kernel_ss) || c(kernel_sp) || c.nat->gs_base_kernel ||
              c.nat->gdt_ents || c.nat->fs_base || c.nat->gs_base_user )
             return -EINVAL;
     }
@@ -745,17 +750,20 @@ int arch_set_info_guest(
 
     if ( has_hvm_container_vcpu(v) )
     {
-        /*
-         * NB: TF_kernel_mode is set unconditionally for HVM guests,
-         * so we always use the gs_base_kernel here. If we change this
-         * function to imitate the PV functionality, we'll need to
-         * make it pay attention to the kernel bit.
-         */
-        hvm_set_info_guest(v, compat ? 0 : c.nat->gs_base_kernel);
 
         if ( is_hvm_vcpu(v) || v->is_initialised )
             goto out;
 
+        if ( c.nat->ctrlreg[0] ) {
+            v->arch.hvm_vcpu.guest_cr[0] |= c.nat->ctrlreg[0];
+            hvm_update_guest_cr(v, 0);
+        }
+
+        if ( c.nat->ctrlreg[4] ) {
+            v->arch.hvm_vcpu.guest_cr[4] |= c.nat->ctrlreg[4];
+            hvm_update_guest_cr(v, 4);
+        }
+
         /* NB: No need to use PV cr3 un-pickling macros */
         cr3_gfn = c(ctrlreg[3]) >> PAGE_SHIFT;
         cr3_page = get_page_from_gfn(d, cr3_gfn, NULL, P2M_ALLOC);
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index f0132a4..8d923e7 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -1467,7 +1467,7 @@ static int vmx_event_pending(struct vcpu *v)
     return intr_info & INTR_INFO_VALID_MASK;
 }
 
-static void vmx_set_info_guest(struct vcpu *v, uint64_t gs_base_kernel)
+static void vmx_set_info_guest(struct vcpu *v)
 {
     unsigned long intr_shadow;
 
@@ -1492,10 +1492,6 @@ static void vmx_set_info_guest(struct vcpu *v, uint64_t gs_base_kernel)
         __vmwrite(GUEST_INTERRUPTIBILITY_INFO, intr_shadow);
     }
 
-    /* PVH 32bitfixme */
-    if ( is_pvh_vcpu(v) )
-        __vmwrite(GUEST_GS_BASE, gs_base_kernel);
-
     vmx_vmcs_exit(v);
 }
 
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index a8ba06d..ccca5df 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -160,7 +160,7 @@ struct hvm_function_table {
     int (*msr_write_intercept)(unsigned int msr, uint64_t msr_content);
     void (*invlpg_intercept)(unsigned long vaddr);
     void (*handle_cd)(struct vcpu *v, unsigned long value);
-    void (*set_info_guest)(struct vcpu *v, uint64_t gs_base_kernel);
+    void (*set_info_guest)(struct vcpu *v);
     void (*set_rdtsc_exiting)(struct vcpu *v, bool_t);
 
     /* Nested HVM */
@@ -434,10 +434,10 @@ void *hvm_map_guest_frame_rw(unsigned long gfn, bool_t permanent);
 void *hvm_map_guest_frame_ro(unsigned long gfn, bool_t permanent);
 void hvm_unmap_guest_frame(void *p, bool_t permanent);
 
-static inline void hvm_set_info_guest(struct vcpu *v, uint64_t gs_base_kernel)
+static inline void hvm_set_info_guest(struct vcpu *v)
 {
     if ( hvm_funcs.set_info_guest )
-        return hvm_funcs.set_info_guest(v, gs_base_kernel);
+        return hvm_funcs.set_info_guest(v);
 }
 
 int hvm_debug_op(struct vcpu *v, int32_t op);
diff --git a/xen/include/public/arch-x86/xen.h b/xen/include/public/arch-x86/xen.h
index 5d220ce..77d1b98 100644
--- a/xen/include/public/arch-x86/xen.h
+++ b/xen/include/public/arch-x86/xen.h
@@ -161,10 +161,10 @@ typedef uint64_t tsc_timestamp_t; /* RDTSC timestamp */
  * - For HVM guests, the structures read include: fpu_ctxt (if
  * VGCT_I387_VALID is set), flags, user_regs, debugreg[*]
  *
- * - PVH guests are the same as HVM guests, but additionally set cr3,
- * and for 64-bit guests, gs_base_kernel.  Additionally, the following
- * entries must be 0: ctrlreg[1], ldt_base, ldt_ents, user_regs.{cs,
- * ss, es, ds, fs, gs), gdt_ents, fs_base, and gs_base_user.
+ * - PVH guests are the same as HVM guests, but additionally use ctrlreg[0] to
+ * set cr0, ctrlreg[3] to set cr3 and ctrlreg[4] to set cr4. The values passed
+ * for cr0 and cr4 will be appended to the default cr0 and cr4 values set by
+ * Xen.
  */
 struct vcpu_guest_context {
     /* FPU registers come first so they can be aligned for FXSAVE/FXRSTOR. */
-- 
1.7.7.5 (Apple Git-26)


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