[Xen-devel] [PATCH 14/18] PVH xen: Checks, asserts, and limitations for PVH

[Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>]

This patch adds some precautionary checks and debug asserts for PVH. Also,
PVH doesn't support any HVM type guest monitoring at present.

Signed-off-by: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
---
 xen/arch/x86/hvm/hvm.c      |   13 +++++++++++++
 xen/arch/x86/hvm/mtrr.c     |    3 +++
 xen/arch/x86/physdev.c      |   13 +++++++++++++
 xen/arch/x86/traps.c        |    5 +++++
 xen/arch/x86/x86_64/traps.c |    2 ++
 5 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 118e21a..888e1f8 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -4520,8 +4520,11 @@ static int hvm_memory_event_traps(long p, uint32_t 
reason,
     return 1;
 }
 
+/* PVH fixme: add support for monitoring guest behaviour in below functions. */
 void hvm_memory_event_cr0(unsigned long value, unsigned long old) 
 {
+    if ( is_pvh_vcpu(current) )
+        return;
     hvm_memory_event_traps(current->domain->arch.hvm_domain
                              .params[HVM_PARAM_MEMORY_EVENT_CR0],
                            MEM_EVENT_REASON_CR0,
@@ -4530,6 +4533,8 @@ void hvm_memory_event_cr0(unsigned long value, unsigned 
long old)
 
 void hvm_memory_event_cr3(unsigned long value, unsigned long old) 
 {
+    if ( is_pvh_vcpu(current) )
+        return;
     hvm_memory_event_traps(current->domain->arch.hvm_domain
                              .params[HVM_PARAM_MEMORY_EVENT_CR3],
                            MEM_EVENT_REASON_CR3,
@@ -4538,6 +4543,8 @@ void hvm_memory_event_cr3(unsigned long value, unsigned 
long old)
 
 void hvm_memory_event_cr4(unsigned long value, unsigned long old) 
 {
+    if ( is_pvh_vcpu(current) )
+        return;
     hvm_memory_event_traps(current->domain->arch.hvm_domain
                              .params[HVM_PARAM_MEMORY_EVENT_CR4],
                            MEM_EVENT_REASON_CR4,
@@ -4546,6 +4553,8 @@ void hvm_memory_event_cr4(unsigned long value, unsigned 
long old)
 
 void hvm_memory_event_msr(unsigned long msr, unsigned long value)
 {
+    if ( is_pvh_vcpu(current) )
+        return;
     hvm_memory_event_traps(current->domain->arch.hvm_domain
                              .params[HVM_PARAM_MEMORY_EVENT_MSR],
                            MEM_EVENT_REASON_MSR,
@@ -4558,6 +4567,8 @@ int hvm_memory_event_int3(unsigned long gla)
     unsigned long gfn;
     gfn = paging_gva_to_gfn(current, gla, &pfec);
 
+    if ( is_pvh_vcpu(current) )
+        return 0;
     return hvm_memory_event_traps(current->domain->arch.hvm_domain
                                     .params[HVM_PARAM_MEMORY_EVENT_INT3],
                                   MEM_EVENT_REASON_INT3,
@@ -4570,6 +4581,8 @@ int hvm_memory_event_single_step(unsigned long gla)
     unsigned long gfn;
     gfn = paging_gva_to_gfn(current, gla, &pfec);
 
+    if ( is_pvh_vcpu(current) )
+        return 0;
     return hvm_memory_event_traps(current->domain->arch.hvm_domain
             .params[HVM_PARAM_MEMORY_EVENT_SINGLE_STEP],
             MEM_EVENT_REASON_SINGLESTEP,
diff --git a/xen/arch/x86/hvm/mtrr.c b/xen/arch/x86/hvm/mtrr.c
index b9d6411..9b377f7 100644
--- a/xen/arch/x86/hvm/mtrr.c
+++ b/xen/arch/x86/hvm/mtrr.c
@@ -578,6 +578,9 @@ int32_t hvm_set_mem_pinned_cacheattr(
 {
     struct hvm_mem_pinned_cacheattr_range *range;
 
+    /* A PVH guest writes to MSR_IA32_CR_PAT natively. */
+    ASSERT(!is_pvh_domain(d));
+
     if ( !((type == PAT_TYPE_UNCACHABLE) ||
            (type == PAT_TYPE_WRCOMB) ||
            (type == PAT_TYPE_WRTHROUGH) ||
diff --git a/xen/arch/x86/physdev.c b/xen/arch/x86/physdev.c
index 3733c7a..2fc7ae6 100644
--- a/xen/arch/x86/physdev.c
+++ b/xen/arch/x86/physdev.c
@@ -475,6 +475,13 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) 
arg)
 
     case PHYSDEVOP_set_iopl: {
         struct physdev_set_iopl set_iopl;
+
+        if ( is_pvh_vcpu(current) )
+        {
+            ret = -EINVAL;
+            break;
+        }
+
         ret = -EFAULT;
         if ( copy_from_guest(&set_iopl, arg, 1) != 0 )
             break;
@@ -488,6 +495,12 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) 
arg)
 
     case PHYSDEVOP_set_iobitmap: {
         struct physdev_set_iobitmap set_iobitmap;
+
+        if ( is_pvh_vcpu(current) )
+        {
+            ret = -EINVAL;
+            break;
+        }
         ret = -EFAULT;
         if ( copy_from_guest(&set_iobitmap, arg, 1) != 0 )
             break;
diff --git a/xen/arch/x86/traps.c b/xen/arch/x86/traps.c
index 0caf73a..6c74e96 100644
--- a/xen/arch/x86/traps.c
+++ b/xen/arch/x86/traps.c
@@ -2709,6 +2709,8 @@ static void emulate_gate_op(struct cpu_user_regs *regs)
     unsigned long off, eip, opnd_off, base, limit;
     int jump;
 
+    ASSERT(!is_pvh_vcpu(v));
+
     /* Check whether this fault is due to the use of a call gate. */
     if ( !read_gate_descriptor(regs->error_code, v, &sel, &off, &ar) ||
          (((ar >> 13) & 3) < (regs->cs & 3)) ||
@@ -3325,6 +3327,9 @@ void do_device_not_available(struct cpu_user_regs *regs)
 
     BUG_ON(!guest_mode(regs));
 
+    /* PVH should not get here. (ctrlreg is not implemented). */
+    ASSERT(!is_pvh_vcpu(curr));
+
     vcpu_restore_fpu_lazy(curr);
 
     if ( curr->arch.pv_vcpu.ctrlreg[0] & X86_CR0_TS )
diff --git a/xen/arch/x86/x86_64/traps.c b/xen/arch/x86/x86_64/traps.c
index bcfd740..29dfe95 100644
--- a/xen/arch/x86/x86_64/traps.c
+++ b/xen/arch/x86/x86_64/traps.c
@@ -440,6 +440,8 @@ static long register_guest_callback(struct 
callback_register *reg)
     long ret = 0;
     struct vcpu *v = current;
 
+    ASSERT(!is_pvh_vcpu(v));
+
     if ( !is_canonical_address(reg->address) )
         return -EINVAL;
 
-- 
1.7.2.3


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