[Xen-devel] [PATCH] xen/altp2m: set access_required properly for all altp2ms

[Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>]

For the hostp2m, access_required starts off as 0, then it can be
set with xc_domain_set_access_required(). However, all the altp2ms
set it to 1 on init, and ignore both the hostp2m and the hypercall.
This patch sets access_required to the value from the hostp2m
on altp2m init, and propagates the values received via hypecall
too all the active altp2ms, when applicable.

Signed-off-by: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
---
 xen/arch/arm/domain.c    |  4 ++++
 xen/arch/x86/domain.c    | 17 +++++++++++++++++
 xen/arch/x86/mm/p2m.c    |  3 ++-
 xen/common/domctl.c      |  2 ++
 xen/include/xen/domain.h |  2 ++
 5 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index ec0f042..1c7d068 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -729,6 +729,10 @@ int arch_domain_soft_reset(struct domain *d)
     return -ENOSYS;
 }
 
+void arch_domain_set_access_required(struct domain *d, bool access_required)
+{
+}
+
 static int is_guest_pv32_psr(uint32_t psr)
 {
     switch (psr & PSR_MODE_MASK)
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 0ca820a..1744b98 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -38,6 +38,7 @@
 #include <xen/livepatch.h>
 #include <public/sysctl.h>
 #include <public/hvm/hvm_vcpu.h>
+#include <asm/altp2m.h>
 #include <asm/regs.h>
 #include <asm/mc146818rtc.h>
 #include <asm/system.h>
@@ -719,6 +720,22 @@ int arch_domain_soft_reset(struct domain *d)
     return ret;
 }
 
+void arch_domain_set_access_required(struct domain *d, bool access_required)
+{
+    unsigned int i;
+
+    if ( !altp2m_active(d) )
+           return;
+
+    for ( i = 0; i < MAX_ALTP2M; i++ )
+    {
+        if ( d->arch.altp2m_eptp[i] == mfn_x(INVALID_MFN) )
+            continue;
+
+        d->arch.altp2m_p2m[i]->access_required = access_required;
+    }
+}
+
 /*
  * These are the masks of CR4 bits (subject to hardware availability) which a
  * PV guest may not legitimiately attempt to modify.
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index c53cab4..8e9fbb5 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -199,6 +199,7 @@ static int p2m_init_altp2m(struct domain *d)
 {
     unsigned int i;
     struct p2m_domain *p2m;
+    struct p2m_domain *hostp2m = p2m_get_hostp2m(d);
 
     mm_lock_init(&d->arch.altp2m_list_lock);
     for ( i = 0; i < MAX_ALTP2M; i++ )
@@ -210,7 +211,7 @@ static int p2m_init_altp2m(struct domain *d)
             return -ENOMEM;
         }
         p2m->p2m_class = p2m_alternate;
-        p2m->access_required = 1;
+        p2m->access_required = hostp2m->access_required;
         _atomic_set(&p2m->active_vcpus, 0);
     }
 
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index 9b7bc08..3ed7708 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -1094,6 +1094,8 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) 
u_domctl)
             domain_pause(d);
             p2m_get_hostp2m(d)->access_required =
                 op->u.access_required.access_required;
+            arch_domain_set_access_required(d,
+                op->u.access_required.access_required);
             domain_unpause(d);
         }
         break;
diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
index 177cb35..9df53a6 100644
--- a/xen/include/xen/domain.h
+++ b/xen/include/xen/domain.h
@@ -66,6 +66,8 @@ void arch_domain_unpause(struct domain *d);
 
 int arch_domain_soft_reset(struct domain *d);
 
+void arch_domain_set_access_required(struct domain *d, bool access_required);
+
 int arch_set_info_guest(struct vcpu *, vcpu_guest_context_u);
 void arch_get_info_guest(struct vcpu *, vcpu_guest_context_u);
 
-- 
2.7.4


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