[Xen-devel] [PATCH v2 46/62] xen/pvshim: set correct domid value

[Wei Liu <wei.liu2@xxxxxxxxxx>]

From: Roger Pau Monne <roger.pau@xxxxxxxxxx>

If domid is not provided by L0 set domid to 1 by default. Note that L0
not provinding the domid can cause trouble if the guest tries to use
it's domid instead of DOMID_SELF when performing hypercalls that are
forwarded to the L0 hypervisor.

Since the domain created is no longer the hardware domain add a hook
to the domain shutdown path in order to forward shutdown operations to
the L0 hypervisor.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Signed-off-by: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>
---
Changes since v1:
 - s/get_dom0_domid/get_initial_domain_id/.
 - Add a comment regarding why dom0 needs to be global.
 - Fix compilation of xen/common/domain.c on ARM.
---
 xen/arch/x86/dom0_build.c       |  2 +-
 xen/arch/x86/guest/xen.c        |  5 +++++
 xen/arch/x86/pv/shim.c          | 21 +++++++++++++++++++++
 xen/arch/x86/setup.c            | 16 +++++++++++-----
 xen/common/domain.c             | 12 ++++++++++++
 xen/include/asm-x86/guest/xen.h |  6 ++++++
 xen/include/asm-x86/pv/shim.h   | 10 ++++++++++
 7 files changed, 66 insertions(+), 6 deletions(-)

diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
index 907acad060..8600123516 100644
--- a/xen/arch/x86/dom0_build.c
+++ b/xen/arch/x86/dom0_build.c
@@ -472,7 +472,7 @@ int __init construct_dom0(struct domain *d, const module_t 
*image,
     int rc;
 
     /* Sanity! */
-    BUG_ON(d->domain_id != 0);
+    BUG_ON(!pv_shim && d->domain_id != 0);
     BUG_ON(d->vcpu[0] == NULL);
     BUG_ON(d->vcpu[0]->is_initialised);
 
diff --git a/xen/arch/x86/guest/xen.c b/xen/arch/x86/guest/xen.c
index 27a6c47753..aff16a0e35 100644
--- a/xen/arch/x86/guest/xen.c
+++ b/xen/arch/x86/guest/xen.c
@@ -322,6 +322,11 @@ const unsigned long *__init 
hypervisor_reserved_pages(unsigned int *size)
     return reserved_pages;
 }
 
+uint32_t hypervisor_cpuid_base(void)
+{
+    return xen_cpuid_base;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/x86/pv/shim.c b/xen/arch/x86/pv/shim.c
index 75365b0697..78351c9ee0 100644
--- a/xen/arch/x86/pv/shim.c
+++ b/xen/arch/x86/pv/shim.c
@@ -20,6 +20,7 @@
  */
 #include <xen/hypercall.h>
 #include <xen/init.h>
+#include <xen/shutdown.h>
 #include <xen/types.h>
 
 #include <asm/apic.h>
@@ -27,6 +28,8 @@
 #include <asm/guest.h>
 #include <asm/pv/mm.h>
 
+#include <public/arch-x86/cpuid.h>
+
 #ifndef CONFIG_PV_SHIM_EXCLUSIVE
 bool pv_shim;
 boolean_param("pv-shim", pv_shim);
@@ -91,6 +94,24 @@ void __init pv_shim_setup_dom(struct domain *d, l4_pgentry_t 
*l4start,
 #undef SET_AND_MAP_PARAM
 }
 
+void pv_shim_shutdown(uint8_t reason)
+{
+    /* XXX: handle suspend */
+    xen_hypercall_shutdown(reason);
+}
+
+domid_t get_initial_domain_id(void)
+{
+    uint32_t eax, ebx, ecx, edx;
+
+    if ( !pv_shim )
+        return 0;
+
+    cpuid(hypervisor_cpuid_base() + 4, &eax, &ebx, &ecx, &edx);
+
+    return (eax & XEN_HVM_CPUID_DOMID_PRESENT) ? ecx : 1;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index b2abcaa278..0f4282c42f 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -104,6 +104,12 @@ unsigned long __read_mostly mmu_cr4_features = 
XEN_MINIMAL_CR4;
 #define SMEP_HVM_ONLY (-1)
 static s8 __initdata opt_smep = 1;
 
+/*
+ * Initial domain place holder. Needs to be global so it can be created in
+ * __start_xen and unpaused in init_done.
+ */
+static struct domain *__initdata dom0;
+
 static int __init parse_smep_param(const char *s)
 {
     if ( !*s )
@@ -576,11 +582,11 @@ static void noinline init_done(void)
 
     system_state = SYS_STATE_active;
 
+    domain_unpause_by_systemcontroller(dom0);
+
     /* MUST be done prior to removing .init data. */
     unregister_init_virtual_region();
 
-    domain_unpause_by_systemcontroller(hardware_domain);
-
     /* Zero the .init code and data. */
     for ( va = __init_begin; va < _p(__init_end); va += PAGE_SIZE )
         clear_page(va);
@@ -659,7 +665,6 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     unsigned long nr_pages, raw_max_page, modules_headroom, *module_map;
     int i, j, e820_warn = 0, bytes = 0;
     bool acpi_boot_table_init_done = false, relocated = false;
-    struct domain *dom0;
     struct ns16550_defaults ns16550 = {
         .data_bits = 8,
         .parity    = 'n',
@@ -1617,11 +1622,12 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     }
 
     /* Create initial domain 0. */
-    dom0 = domain_create(0, domcr_flags, 0, &config);
+    dom0 = domain_create(get_initial_domain_id(), domcr_flags, 0, &config);
     if ( IS_ERR(dom0) || (alloc_dom0_vcpu0(dom0) == NULL) )
         panic("Error creating domain 0");
 
-    dom0->is_privileged = 1;
+    if ( !pv_shim )
+        dom0->is_privileged = 1;
     dom0->target = NULL;
 
     /* Grab the DOM0 command line. */
diff --git a/xen/common/domain.c b/xen/common/domain.c
index 7af8d12512..ef566f7f45 100644
--- a/xen/common/domain.c
+++ b/xen/common/domain.c
@@ -43,6 +43,10 @@
 #include <xen/tmem.h>
 #include <asm/setup.h>
 
+#ifdef CONFIG_X86
+#include <asm/guest.h>
+#endif
+
 /* Linux config option: propageted to domain0 */
 /* xen_processor_pmbits: xen control Cx, Px, ... */
 unsigned int xen_processor_pmbits = XEN_PROCESSOR_PM_PX;
@@ -697,6 +701,14 @@ void domain_shutdown(struct domain *d, u8 reason)
 {
     struct vcpu *v;
 
+#ifdef CONFIG_X86
+    if ( pv_shim )
+    {
+        pv_shim_shutdown(reason);
+        return;
+    }
+#endif
+
     spin_lock(&d->shutdown_lock);
 
     if ( d->shutdown_code == SHUTDOWN_CODE_INVALID )
diff --git a/xen/include/asm-x86/guest/xen.h b/xen/include/asm-x86/guest/xen.h
index 62255fda8b..ac48dcbe44 100644
--- a/xen/include/asm-x86/guest/xen.h
+++ b/xen/include/asm-x86/guest/xen.h
@@ -38,6 +38,7 @@ int hypervisor_alloc_unused_page(mfn_t *mfn);
 int hypervisor_free_unused_page(mfn_t mfn);
 void hypervisor_fixup_e820(struct e820map *e820);
 const unsigned long *hypervisor_reserved_pages(unsigned int *size);
+uint32_t hypervisor_cpuid_base(void);
 
 DECLARE_PER_CPU(unsigned int, vcpu_id);
 DECLARE_PER_CPU(struct vcpu_info *, vcpu_info);
@@ -66,6 +67,11 @@ static inline const unsigned long 
*hypervisor_reserved_pages(unsigned int *size)
     ASSERT_UNREACHABLE();
     return NULL;
 };
+static inline uint32_t hypervisor_cpuid_base(void)
+{
+    ASSERT_UNREACHABLE();
+    return 0;
+};
 
 #endif /* CONFIG_XEN_GUEST */
 #endif /* __X86_GUEST_XEN_H__ */
diff --git a/xen/include/asm-x86/pv/shim.h b/xen/include/asm-x86/pv/shim.h
index b0c361cba1..ff7c050dc6 100644
--- a/xen/include/asm-x86/pv/shim.h
+++ b/xen/include/asm-x86/pv/shim.h
@@ -35,6 +35,8 @@ void pv_shim_setup_dom(struct domain *d, l4_pgentry_t 
*l4start,
                        unsigned long va_start, unsigned long store_va,
                        unsigned long console_va, unsigned long vphysmap,
                        start_info_t *si);
+void pv_shim_shutdown(uint8_t reason);
+domid_t get_initial_domain_id(void);
 
 #else
 
@@ -47,6 +49,14 @@ static inline void pv_shim_setup_dom(struct domain *d, 
l4_pgentry_t *l4start,
 {
     ASSERT_UNREACHABLE();
 }
+static inline void pv_shim_shutdown(uint8_t reason)
+{
+    ASSERT_UNREACHABLE();
+}
+static inline domid_t get_initial_domain_id(void)
+{
+    return 0;
+}
 
 #endif
 
-- 
2.11.0


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