[PATCH 0/4] x86/boot: Misc improvements to dom0 construction

[PATCH 0/4] x86/boot: Misc improvements to dom0 construction

[Andrew Cooper]

This started out as just patch 3, trying to clean up the remains of the
pv-l1tf debugging, and expanded a little upon reading the surrounding code.

Andrew Cooper (4):
  x86/pv: Fix error handling in dom0_construct_pv()
  x86/boot: Rename dom0_{pvh,verbose} variables to have an opt_ prefix
  x86/boot: Wire up dom0=shadow for PV dom0
  x86/boot: Link opt_dom0_verbose to CONFIG_VERBOSE_DEBUG

 docs/misc/xen-command-line.pandoc | 17 +++++++++++------
 xen/arch/x86/dom0_build.c         | 20 ++++++--------------
 xen/arch/x86/hvm/dom0_build.c     |  2 +-
 xen/arch/x86/pv/dom0_build.c      | 26 +++++++++++++++-----------
 xen/arch/x86/setup.c              |  2 +-
 xen/include/asm-x86/setup.h       |  4 ++--
 6 files changed, 36 insertions(+), 35 deletions(-)

-- 
2.1.4


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[Xen-devel] [PATCH 0/4] x86/boot: Misc improvements to dom0 construction

[Andrew Cooper]

This started out as just patch 3, trying to clean up the remains of the
pv-l1tf debugging, and expanded a little upon reading the surrounding code.

Andrew Cooper (4):
  x86/pv: Fix error handling in dom0_construct_pv()
  x86/boot: Rename dom0_{pvh,verbose} variables to have an opt_ prefix
  x86/boot: Wire up dom0=shadow for PV dom0
  x86/boot: Link opt_dom0_verbose to CONFIG_VERBOSE_DEBUG

 docs/misc/xen-command-line.pandoc | 17 +++++++++++------
 xen/arch/x86/dom0_build.c         | 20 ++++++--------------
 xen/arch/x86/hvm/dom0_build.c     |  2 +-
 xen/arch/x86/pv/dom0_build.c      | 26 +++++++++++++++-----------
 xen/arch/x86/setup.c              |  2 +-
 xen/include/asm-x86/setup.h       |  4 ++--
 6 files changed, 36 insertions(+), 35 deletions(-)

-- 
2.1.4


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[PATCH 1/4] x86/pv: Fix error handling in dom0_construct_pv()

[Andrew Cooper]

One path in dom0_construct_pv() returns -1 unlike all other error paths.
Switch it to returning -EINVAL.

This was last modified by c/s c84481fb XSA-55, but the bug predates that
series.  However, this patch did (for no obvious reason) introduce a
bifurcated tail to the function with two subtly different elf_check_broken()
clauses.

As the elf_check_broken() is just a warning and doesn't influence the further
boot, fold the exit paths together and use a single clause.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
---
 xen/arch/x86/pv/dom0_build.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c
index cef2d42..064a10e 100644
--- a/xen/arch/x86/pv/dom0_build.c
+++ b/xen/arch/x86/pv/dom0_build.c
@@ -735,7 +735,7 @@ int __init dom0_construct_pv(struct domain *d,
             mapcache_override_current(NULL);
             switch_cr3_cr4(current->arch.cr3, read_cr4());
             printk("Invalid HYPERCALL_PAGE field in ELF notes.\n");
-            rc = -1;
+            rc = -EINVAL;
             goto out;
         }
         hypercall_page_initialise(
@@ -903,21 +903,15 @@ int __init dom0_construct_pv(struct domain *d,
     rc = dom0_setup_permissions(d);
     BUG_ON(rc != 0);
 
-    if ( elf_check_broken(&elf) )
-        printk(" Xen warning: dom0 kernel broken ELF: %s\n",
-               elf_check_broken(&elf));
-
     if ( d->domain_id == hardware_domid )
         iommu_hwdom_init(d);
 
     v->is_initialised = 1;
     clear_bit(_VPF_down, &v->pause_flags);
 
-    return 0;
-
 out:
     if ( elf_check_broken(&elf) )
-        printk(" Xen dom0 kernel broken ELF: %s\n",
+        printk(XENLOG_WARNING "Dom0 kernel broken ELF: %s\n",
                elf_check_broken(&elf));
 
     return rc;
-- 
2.1.4


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[Xen-devel] [PATCH 1/4] x86/pv: Fix error handling in dom0_construct_pv()

[Andrew Cooper]

One path in dom0_construct_pv() returns -1 unlike all other error paths.
Switch it to returning -EINVAL.

This was last modified by c/s c84481fb XSA-55, but the bug predates that
series.  However, this patch did (for no obvious reason) introduce a
bifurcated tail to the function with two subtly different elf_check_broken()
clauses.

As the elf_check_broken() is just a warning and doesn't influence the further
boot, fold the exit paths together and use a single clause.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
---
 xen/arch/x86/pv/dom0_build.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c
index cef2d42..064a10e 100644
--- a/xen/arch/x86/pv/dom0_build.c
+++ b/xen/arch/x86/pv/dom0_build.c
@@ -735,7 +735,7 @@ int __init dom0_construct_pv(struct domain *d,
             mapcache_override_current(NULL);
             switch_cr3_cr4(current->arch.cr3, read_cr4());
             printk("Invalid HYPERCALL_PAGE field in ELF notes.\n");
-            rc = -1;
+            rc = -EINVAL;
             goto out;
         }
         hypercall_page_initialise(
@@ -903,21 +903,15 @@ int __init dom0_construct_pv(struct domain *d,
     rc = dom0_setup_permissions(d);
     BUG_ON(rc != 0);
 
-    if ( elf_check_broken(&elf) )
-        printk(" Xen warning: dom0 kernel broken ELF: %s\n",
-               elf_check_broken(&elf));
-
     if ( d->domain_id == hardware_domid )
         iommu_hwdom_init(d);
 
     v->is_initialised = 1;
     clear_bit(_VPF_down, &v->pause_flags);
 
-    return 0;
-
 out:
     if ( elf_check_broken(&elf) )
-        printk(" Xen dom0 kernel broken ELF: %s\n",
+        printk(XENLOG_WARNING "Dom0 kernel broken ELF: %s\n",
                elf_check_broken(&elf));
 
     return rc;
-- 
2.1.4


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[PATCH 2/4] x86/boot: Rename dom0_{pvh, verbose} variables to have an opt_ prefix

[Andrew Cooper]

For consistency with other command line options.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
---
 xen/arch/x86/dom0_build.c     | 12 ++++++------
 xen/arch/x86/hvm/dom0_build.c |  2 +-
 xen/arch/x86/setup.c          |  2 +-
 xen/include/asm-x86/setup.h   |  4 ++--
 4 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
index 73f5407..27315d5 100644
--- a/xen/arch/x86/dom0_build.c
+++ b/xen/arch/x86/dom0_build.c
@@ -261,7 +261,7 @@ unsigned int __init dom0_max_vcpus(void)
         max_vcpus = opt_dom0_max_vcpus_min;
     if ( opt_dom0_max_vcpus_max < max_vcpus )
         max_vcpus = opt_dom0_max_vcpus_max;
-    limit = dom0_pvh ? HVM_MAX_VCPUS : MAX_VIRT_CPUS;
+    limit = opt_dom0_pvh ? HVM_MAX_VCPUS : MAX_VIRT_CPUS;
     if ( max_vcpus > limit )
         max_vcpus = limit;
 
@@ -280,8 +280,8 @@ struct vcpu *__init alloc_dom0_vcpu0(struct domain *dom0)
 #ifdef CONFIG_SHADOW_PAGING
 bool __initdata opt_dom0_shadow;
 #endif
-bool __initdata dom0_pvh = !IS_ENABLED(CONFIG_PV);
-bool __initdata dom0_verbose;
+bool __initdata opt_dom0_pvh = !IS_ENABLED(CONFIG_PV);
+bool __initdata opt_dom0_verbose;
 
 static int __init parse_dom0_param(const char *s)
 {
@@ -296,15 +296,15 @@ static int __init parse_dom0_param(const char *s)
             ss = strchr(s, '\0');
 
         if ( IS_ENABLED(CONFIG_PV) && !cmdline_strcmp(s, "pv") )
-            dom0_pvh = false;
+            opt_dom0_pvh = false;
         else if ( IS_ENABLED(CONFIG_HVM) && !cmdline_strcmp(s, "pvh") )
-            dom0_pvh = true;
+            opt_dom0_pvh = true;
 #ifdef CONFIG_SHADOW_PAGING
         else if ( (val = parse_boolean("shadow", s, ss)) >= 0 )
             opt_dom0_shadow = val;
 #endif
         else if ( (val = parse_boolean("verbose", s, ss)) >= 0 )
-            dom0_verbose = val;
+            opt_dom0_verbose = val;
         else
             rc = -EINVAL;
 
diff --git a/xen/arch/x86/hvm/dom0_build.c b/xen/arch/x86/hvm/dom0_build.c
index aa599f0..8845399 100644
--- a/xen/arch/x86/hvm/dom0_build.c
+++ b/xen/arch/x86/hvm/dom0_build.c
@@ -484,7 +484,7 @@ static int __init pvh_populate_p2m(struct domain *d)
             return rc;
     }
 
-    if ( dom0_verbose )
+    if ( opt_dom0_verbose )
         print_order_stats(d);
 
     return 0;
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 9566b1d..0ed94a6 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1713,7 +1713,7 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     init_guest_cpuid();
     init_guest_msr_policy();
 
-    if ( dom0_pvh )
+    if ( opt_dom0_pvh )
     {
         dom0_cfg.flags |= (XEN_DOMCTL_CDF_hvm_guest |
                            ((hvm_hap_supported() && !opt_dom0_shadow) ?
diff --git a/xen/include/asm-x86/setup.h b/xen/include/asm-x86/setup.h
index bb4c385..15d6363 100644
--- a/xen/include/asm-x86/setup.h
+++ b/xen/include/asm-x86/setup.h
@@ -64,8 +64,8 @@ extern bool opt_dom0_shadow;
 #else
 #define opt_dom0_shadow false
 #endif
-extern bool dom0_pvh;
-extern bool dom0_verbose;
+extern bool opt_dom0_pvh;
+extern bool opt_dom0_verbose;
 
 #define max_init_domid (0)
 
-- 
2.1.4


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[Xen-devel] [PATCH 2/4] x86/boot: Rename dom0_{pvh, verbose} variables to have an opt_ prefix

[Andrew Cooper]

For consistency with other command line options.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
---
 xen/arch/x86/dom0_build.c     | 12 ++++++------
 xen/arch/x86/hvm/dom0_build.c |  2 +-
 xen/arch/x86/setup.c          |  2 +-
 xen/include/asm-x86/setup.h   |  4 ++--
 4 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
index 73f5407..27315d5 100644
--- a/xen/arch/x86/dom0_build.c
+++ b/xen/arch/x86/dom0_build.c
@@ -261,7 +261,7 @@ unsigned int __init dom0_max_vcpus(void)
         max_vcpus = opt_dom0_max_vcpus_min;
     if ( opt_dom0_max_vcpus_max < max_vcpus )
         max_vcpus = opt_dom0_max_vcpus_max;
-    limit = dom0_pvh ? HVM_MAX_VCPUS : MAX_VIRT_CPUS;
+    limit = opt_dom0_pvh ? HVM_MAX_VCPUS : MAX_VIRT_CPUS;
     if ( max_vcpus > limit )
         max_vcpus = limit;
 
@@ -280,8 +280,8 @@ struct vcpu *__init alloc_dom0_vcpu0(struct domain *dom0)
 #ifdef CONFIG_SHADOW_PAGING
 bool __initdata opt_dom0_shadow;
 #endif
-bool __initdata dom0_pvh = !IS_ENABLED(CONFIG_PV);
-bool __initdata dom0_verbose;
+bool __initdata opt_dom0_pvh = !IS_ENABLED(CONFIG_PV);
+bool __initdata opt_dom0_verbose;
 
 static int __init parse_dom0_param(const char *s)
 {
@@ -296,15 +296,15 @@ static int __init parse_dom0_param(const char *s)
             ss = strchr(s, '\0');
 
         if ( IS_ENABLED(CONFIG_PV) && !cmdline_strcmp(s, "pv") )
-            dom0_pvh = false;
+            opt_dom0_pvh = false;
         else if ( IS_ENABLED(CONFIG_HVM) && !cmdline_strcmp(s, "pvh") )
-            dom0_pvh = true;
+            opt_dom0_pvh = true;
 #ifdef CONFIG_SHADOW_PAGING
         else if ( (val = parse_boolean("shadow", s, ss)) >= 0 )
             opt_dom0_shadow = val;
 #endif
         else if ( (val = parse_boolean("verbose", s, ss)) >= 0 )
-            dom0_verbose = val;
+            opt_dom0_verbose = val;
         else
             rc = -EINVAL;
 
diff --git a/xen/arch/x86/hvm/dom0_build.c b/xen/arch/x86/hvm/dom0_build.c
index aa599f0..8845399 100644
--- a/xen/arch/x86/hvm/dom0_build.c
+++ b/xen/arch/x86/hvm/dom0_build.c
@@ -484,7 +484,7 @@ static int __init pvh_populate_p2m(struct domain *d)
             return rc;
     }
 
-    if ( dom0_verbose )
+    if ( opt_dom0_verbose )
         print_order_stats(d);
 
     return 0;
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 9566b1d..0ed94a6 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1713,7 +1713,7 @@ void __init noreturn __start_xen(unsigned long mbi_p)
     init_guest_cpuid();
     init_guest_msr_policy();
 
-    if ( dom0_pvh )
+    if ( opt_dom0_pvh )
     {
         dom0_cfg.flags |= (XEN_DOMCTL_CDF_hvm_guest |
                            ((hvm_hap_supported() && !opt_dom0_shadow) ?
diff --git a/xen/include/asm-x86/setup.h b/xen/include/asm-x86/setup.h
index bb4c385..15d6363 100644
--- a/xen/include/asm-x86/setup.h
+++ b/xen/include/asm-x86/setup.h
@@ -64,8 +64,8 @@ extern bool opt_dom0_shadow;
 #else
 #define opt_dom0_shadow false
 #endif
-extern bool dom0_pvh;
-extern bool dom0_verbose;
+extern bool opt_dom0_pvh;
+extern bool opt_dom0_verbose;
 
 #define max_init_domid (0)
 
-- 
2.1.4


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[PATCH 3/4] x86/boot: Wire up dom0=shadow for PV dom0

[Andrew Cooper]

This would have been very handy when debugging some pv-l1tf issues.  As there
is no cost to supporting it, wire it up.

Due to the way dom0 is constructed, switching into shadow mode must be done
after the pagetables are written, and because of partially being in dom0
context, shadow_enable() doesn't like the state it finds.

Reuse the pv_l1tf tasklet for convenience, which will switch dom0 into shadow
mode just before it starts executing.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
---
 docs/misc/xen-command-line.pandoc | 14 +++++++++-----
 xen/arch/x86/dom0_build.c         |  8 --------
 xen/arch/x86/pv/dom0_build.c      |  9 +++++++++
 3 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/docs/misc/xen-command-line.pandoc b/docs/misc/xen-command-line.pandoc
index 1fc1802..e6d241e 100644
--- a/docs/misc/xen-command-line.pandoc
+++ b/docs/misc/xen-command-line.pandoc
@@ -675,12 +675,16 @@ Controls for how dom0 is constructed on x86 systems.
         selected mode.
     *   For a PVH dom0, the hardware must have VT-x/SVM extensions available.
 
-*   The `shadow` boolean is only applicable when dom0 is constructed as a PVH
-    guest, and controls whether dom0 uses hardware assisted paging, or shadow
-    paging.  The default is HAP when available, and shadow otherwise.
+*   The `shadow` boolean allows dom0 to be explicitly constructed using shadow
+    paging.  This option is unavailable when `CONFIG_SHADOW_PAGING` is
+    disabled.
 
-    This option is unavailable when `CONFIG_SHADOW_PAGING` is disabled.  Such
-    builds of Xen require HAP-capable hardware to use a PVH dom0.
+    For PVH, dom0 defaults to using HAP on capable hardware, and falls back to
+    shadow paging otherwise.  A PVH dom0 cannot be used if Xen is compiled
+    without paging support, and the hardware lacks HAP support.
+
+    For PV, the use of dom0 shadow mode is only for development purposes.  PV
+    guests do no require any paging support by default.
 
 *   The `verbose` boolean is intended for diagnostics, and prints out extra
     information during the dom0 build.  It defaults to false.
diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
index 27315d5..93e5531 100644
--- a/xen/arch/x86/dom0_build.c
+++ b/xen/arch/x86/dom0_build.c
@@ -588,14 +588,6 @@ int __init construct_dom0(struct domain *d, const module_t *image,
 
     process_pending_softirqs();
 
-#ifdef CONFIG_SHADOW_PAGING
-    if ( opt_dom0_shadow && !dom0_pvh )
-    {
-        opt_dom0_shadow = false;
-        printk(XENLOG_WARNING "Shadow Dom0 requires PVH. Option ignored.\n");
-    }
-#endif
-
     if ( is_hvm_domain(d) )
         rc = dom0_construct_pvh(d, image, image_headroom, initrd, cmdline);
     else if ( is_pv_domain(d) )
diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c
index 064a10e..4a1526a 100644
--- a/xen/arch/x86/pv/dom0_build.c
+++ b/xen/arch/x86/pv/dom0_build.c
@@ -906,6 +906,15 @@ int __init dom0_construct_pv(struct domain *d,
     if ( d->domain_id == hardware_domid )
         iommu_hwdom_init(d);
 
+    /* Activate shadow mode, if requested.  Reuse the pv_l1tf tasklet. */
+#ifdef CONFIG_SHADOW_PAGING
+    if ( opt_dom0_shadow )
+    {
+        printk("Switching dom0 to using shadow paging\n");
+        tasklet_schedule(&d->arch.paging.shadow.pv_l1tf_tasklet);
+    }
+#endif
+
     v->is_initialised = 1;
     clear_bit(_VPF_down, &v->pause_flags);
 
-- 
2.1.4


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[Xen-devel] [PATCH 3/4] x86/boot: Wire up dom0=shadow for PV dom0

[Andrew Cooper]

This would have been very handy when debugging some pv-l1tf issues.  As there
is no cost to supporting it, wire it up.

Due to the way dom0 is constructed, switching into shadow mode must be done
after the pagetables are written, and because of partially being in dom0
context, shadow_enable() doesn't like the state it finds.

Reuse the pv_l1tf tasklet for convenience, which will switch dom0 into shadow
mode just before it starts executing.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
---
 docs/misc/xen-command-line.pandoc | 14 +++++++++-----
 xen/arch/x86/dom0_build.c         |  8 --------
 xen/arch/x86/pv/dom0_build.c      |  9 +++++++++
 3 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/docs/misc/xen-command-line.pandoc b/docs/misc/xen-command-line.pandoc
index 1fc1802..e6d241e 100644
--- a/docs/misc/xen-command-line.pandoc
+++ b/docs/misc/xen-command-line.pandoc
@@ -675,12 +675,16 @@ Controls for how dom0 is constructed on x86 systems.
         selected mode.
     *   For a PVH dom0, the hardware must have VT-x/SVM extensions available.
 
-*   The `shadow` boolean is only applicable when dom0 is constructed as a PVH
-    guest, and controls whether dom0 uses hardware assisted paging, or shadow
-    paging.  The default is HAP when available, and shadow otherwise.
+*   The `shadow` boolean allows dom0 to be explicitly constructed using shadow
+    paging.  This option is unavailable when `CONFIG_SHADOW_PAGING` is
+    disabled.
 
-    This option is unavailable when `CONFIG_SHADOW_PAGING` is disabled.  Such
-    builds of Xen require HAP-capable hardware to use a PVH dom0.
+    For PVH, dom0 defaults to using HAP on capable hardware, and falls back to
+    shadow paging otherwise.  A PVH dom0 cannot be used if Xen is compiled
+    without paging support, and the hardware lacks HAP support.
+
+    For PV, the use of dom0 shadow mode is only for development purposes.  PV
+    guests do no require any paging support by default.
 
 *   The `verbose` boolean is intended for diagnostics, and prints out extra
     information during the dom0 build.  It defaults to false.
diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
index 27315d5..93e5531 100644
--- a/xen/arch/x86/dom0_build.c
+++ b/xen/arch/x86/dom0_build.c
@@ -588,14 +588,6 @@ int __init construct_dom0(struct domain *d, const module_t *image,
 
     process_pending_softirqs();
 
-#ifdef CONFIG_SHADOW_PAGING
-    if ( opt_dom0_shadow && !dom0_pvh )
-    {
-        opt_dom0_shadow = false;
-        printk(XENLOG_WARNING "Shadow Dom0 requires PVH. Option ignored.\n");
-    }
-#endif
-
     if ( is_hvm_domain(d) )
         rc = dom0_construct_pvh(d, image, image_headroom, initrd, cmdline);
     else if ( is_pv_domain(d) )
diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c
index 064a10e..4a1526a 100644
--- a/xen/arch/x86/pv/dom0_build.c
+++ b/xen/arch/x86/pv/dom0_build.c
@@ -906,6 +906,15 @@ int __init dom0_construct_pv(struct domain *d,
     if ( d->domain_id == hardware_domid )
         iommu_hwdom_init(d);
 
+    /* Activate shadow mode, if requested.  Reuse the pv_l1tf tasklet. */
+#ifdef CONFIG_SHADOW_PAGING
+    if ( opt_dom0_shadow )
+    {
+        printk("Switching dom0 to using shadow paging\n");
+        tasklet_schedule(&d->arch.paging.shadow.pv_l1tf_tasklet);
+    }
+#endif
+
     v->is_initialised = 1;
     clear_bit(_VPF_down, &v->pause_flags);
 
-- 
2.1.4


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[PATCH 4/4] x86/boot: Link opt_dom0_verbose to CONFIG_VERBOSE_DEBUG

[Andrew Cooper]

We currently have an asymmetric setup where CONFIG_VERBOSE_DEBUG controls
extra diagnostics for a PV dom0, and opt_dom0_verbose controls extra
diagnostics for a PVH dom0.

Default opt_dom0_verbose to CONFIG_VERBOSE_DEBUG and use opt_dom0_verbose
consistently.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
---
 docs/misc/xen-command-line.pandoc | 3 ++-
 xen/arch/x86/dom0_build.c         | 2 +-
 xen/arch/x86/pv/dom0_build.c      | 7 ++++---
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/docs/misc/xen-command-line.pandoc b/docs/misc/xen-command-line.pandoc
index e6d241e..51dc8ae 100644
--- a/docs/misc/xen-command-line.pandoc
+++ b/docs/misc/xen-command-line.pandoc
@@ -687,7 +687,8 @@ Controls for how dom0 is constructed on x86 systems.
     guests do no require any paging support by default.
 
 *   The `verbose` boolean is intended for diagnostics, and prints out extra
-    information during the dom0 build.  It defaults to false.
+    information during the dom0 build.  It defaults to the compile time choice
+    of `CONFIG_VERBOSE_DEBUG`.
 
 ### dom0-iommu
     = List of [ passthrough=<bool>, strict=<bool>, map-inclusive=<bool>,
diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
index 93e5531..9b06363 100644
--- a/xen/arch/x86/dom0_build.c
+++ b/xen/arch/x86/dom0_build.c
@@ -281,7 +281,7 @@ struct vcpu *__init alloc_dom0_vcpu0(struct domain *dom0)
 bool __initdata opt_dom0_shadow;
 #endif
 bool __initdata opt_dom0_pvh = !IS_ENABLED(CONFIG_PV);
-bool __initdata opt_dom0_verbose;
+bool __initdata opt_dom0_verbose = IS_ENABLED(CONFIG_VERBOSE_DEBUG);
 
 static int __init parse_dom0_param(const char *s)
 {
diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c
index 4a1526a..903611f 100644
--- a/xen/arch/x86/pv/dom0_build.c
+++ b/xen/arch/x86/pv/dom0_build.c
@@ -345,9 +345,10 @@ int __init dom0_construct_pv(struct domain *d,
 
     if ( (rc = elf_init(&elf, image_start, image_len)) != 0 )
         return rc;
-#ifdef CONFIG_VERBOSE_DEBUG
-    elf_set_verbose(&elf);
-#endif
+
+    if ( opt_dom0_verbose )
+        elf_set_verbose(&elf);
+
     elf_parse_binary(&elf);
     if ( (rc = elf_xen_parse(&elf, &parms)) != 0 )
         goto out;
-- 
2.1.4


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[Xen-devel] [PATCH 4/4] x86/boot: Link opt_dom0_verbose to CONFIG_VERBOSE_DEBUG

[Andrew Cooper]

We currently have an asymmetric setup where CONFIG_VERBOSE_DEBUG controls
extra diagnostics for a PV dom0, and opt_dom0_verbose controls extra
diagnostics for a PVH dom0.

Default opt_dom0_verbose to CONFIG_VERBOSE_DEBUG and use opt_dom0_verbose
consistently.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
---
 docs/misc/xen-command-line.pandoc | 3 ++-
 xen/arch/x86/dom0_build.c         | 2 +-
 xen/arch/x86/pv/dom0_build.c      | 7 ++++---
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/docs/misc/xen-command-line.pandoc b/docs/misc/xen-command-line.pandoc
index e6d241e..51dc8ae 100644
--- a/docs/misc/xen-command-line.pandoc
+++ b/docs/misc/xen-command-line.pandoc
@@ -687,7 +687,8 @@ Controls for how dom0 is constructed on x86 systems.
     guests do no require any paging support by default.
 
 *   The `verbose` boolean is intended for diagnostics, and prints out extra
-    information during the dom0 build.  It defaults to false.
+    information during the dom0 build.  It defaults to the compile time choice
+    of `CONFIG_VERBOSE_DEBUG`.
 
 ### dom0-iommu
     = List of [ passthrough=<bool>, strict=<bool>, map-inclusive=<bool>,
diff --git a/xen/arch/x86/dom0_build.c b/xen/arch/x86/dom0_build.c
index 93e5531..9b06363 100644
--- a/xen/arch/x86/dom0_build.c
+++ b/xen/arch/x86/dom0_build.c
@@ -281,7 +281,7 @@ struct vcpu *__init alloc_dom0_vcpu0(struct domain *dom0)
 bool __initdata opt_dom0_shadow;
 #endif
 bool __initdata opt_dom0_pvh = !IS_ENABLED(CONFIG_PV);
-bool __initdata opt_dom0_verbose;
+bool __initdata opt_dom0_verbose = IS_ENABLED(CONFIG_VERBOSE_DEBUG);
 
 static int __init parse_dom0_param(const char *s)
 {
diff --git a/xen/arch/x86/pv/dom0_build.c b/xen/arch/x86/pv/dom0_build.c
index 4a1526a..903611f 100644
--- a/xen/arch/x86/pv/dom0_build.c
+++ b/xen/arch/x86/pv/dom0_build.c
@@ -345,9 +345,10 @@ int __init dom0_construct_pv(struct domain *d,
 
     if ( (rc = elf_init(&elf, image_start, image_len)) != 0 )
         return rc;
-#ifdef CONFIG_VERBOSE_DEBUG
-    elf_set_verbose(&elf);
-#endif
+
+    if ( opt_dom0_verbose )
+        elf_set_verbose(&elf);
+
     elf_parse_binary(&elf);
     if ( (rc = elf_xen_parse(&elf, &parms)) != 0 )
         goto out;
-- 
2.1.4


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Re: [PATCH 1/4] x86/pv: Fix error handling in dom0_construct_pv()

[Jan Beulich]

>>> On 20.05.19 at 12:18, <andrew.cooper3@citrix.com> wrote:
> One path in dom0_construct_pv() returns -1 unlike all other error paths.
> Switch it to returning -EINVAL.
> 
> This was last modified by c/s c84481fb XSA-55, but the bug predates that
> series.  However, this patch did (for no obvious reason) introduce a
> bifurcated tail to the function with two subtly different elf_check_broken()
> clauses.
> 
> As the elf_check_broken() is just a warning and doesn't influence the further
> boot, fold the exit paths together and use a single clause.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Reviewed-by: Jan Beulich <jbeulich@suse.com>



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Re: [Xen-devel] [PATCH 1/4] x86/pv: Fix error handling in dom0_construct_pv()

[Jan Beulich]

>>> On 20.05.19 at 12:18, <andrew.cooper3@citrix.com> wrote:
> One path in dom0_construct_pv() returns -1 unlike all other error paths.
> Switch it to returning -EINVAL.
> 
> This was last modified by c/s c84481fb XSA-55, but the bug predates that
> series.  However, this patch did (for no obvious reason) introduce a
> bifurcated tail to the function with two subtly different elf_check_broken()
> clauses.
> 
> As the elf_check_broken() is just a warning and doesn't influence the further
> boot, fold the exit paths together and use a single clause.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Reviewed-by: Jan Beulich <jbeulich@suse.com>



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Re: [PATCH 2/4] x86/boot: Rename dom0_{pvh, verbose} variables to have an opt_ prefix

[Jan Beulich]

>>> On 20.05.19 at 12:18, <andrew.cooper3@citrix.com> wrote:
> For consistency with other command line options.
> 
> No functional change.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Acked-by: Jan Beulich <jbeulich@suse.com>



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Re: [Xen-devel] [PATCH 2/4] x86/boot: Rename dom0_{pvh, verbose} variables to have an opt_ prefix

[Jan Beulich]

>>> On 20.05.19 at 12:18, <andrew.cooper3@citrix.com> wrote:
> For consistency with other command line options.
> 
> No functional change.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Acked-by: Jan Beulich <jbeulich@suse.com>



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Re: [PATCH 3/4] x86/boot: Wire up dom0=shadow for PV dom0

[Jan Beulich]

>>> On 20.05.19 at 12:18, <andrew.cooper3@citrix.com> wrote:
> --- a/docs/misc/xen-command-line.pandoc
> +++ b/docs/misc/xen-command-line.pandoc
> @@ -675,12 +675,16 @@ Controls for how dom0 is constructed on x86 systems.
>          selected mode.
>      *   For a PVH dom0, the hardware must have VT-x/SVM extensions 
> available.
>  
> -*   The `shadow` boolean is only applicable when dom0 is constructed as a PVH
> -    guest, and controls whether dom0 uses hardware assisted paging, or shadow
> -    paging.  The default is HAP when available, and shadow otherwise.
> +*   The `shadow` boolean allows dom0 to be explicitly constructed using shadow
> +    paging.  This option is unavailable when `CONFIG_SHADOW_PAGING` is
> +    disabled.
>  
> -    This option is unavailable when `CONFIG_SHADOW_PAGING` is disabled.  Such
> -    builds of Xen require HAP-capable hardware to use a PVH dom0.
> +    For PVH, dom0 defaults to using HAP on capable hardware, and falls back to
> +    shadow paging otherwise.  A PVH dom0 cannot be used if Xen is compiled
> +    without paging support, and the hardware lacks HAP support.

I think you want to add another "shadow" ahead of "paging" here.
Other than this
Reviewed-by: Jan Beulich <jbeulich@suse.com>

Jan



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Re: [Xen-devel] [PATCH 3/4] x86/boot: Wire up dom0=shadow for PV dom0

[Jan Beulich]

>>> On 20.05.19 at 12:18, <andrew.cooper3@citrix.com> wrote:
> --- a/docs/misc/xen-command-line.pandoc
> +++ b/docs/misc/xen-command-line.pandoc
> @@ -675,12 +675,16 @@ Controls for how dom0 is constructed on x86 systems.
>          selected mode.
>      *   For a PVH dom0, the hardware must have VT-x/SVM extensions 
> available.
>  
> -*   The `shadow` boolean is only applicable when dom0 is constructed as a PVH
> -    guest, and controls whether dom0 uses hardware assisted paging, or shadow
> -    paging.  The default is HAP when available, and shadow otherwise.
> +*   The `shadow` boolean allows dom0 to be explicitly constructed using shadow
> +    paging.  This option is unavailable when `CONFIG_SHADOW_PAGING` is
> +    disabled.
>  
> -    This option is unavailable when `CONFIG_SHADOW_PAGING` is disabled.  Such
> -    builds of Xen require HAP-capable hardware to use a PVH dom0.
> +    For PVH, dom0 defaults to using HAP on capable hardware, and falls back to
> +    shadow paging otherwise.  A PVH dom0 cannot be used if Xen is compiled
> +    without paging support, and the hardware lacks HAP support.

I think you want to add another "shadow" ahead of "paging" here.
Other than this
Reviewed-by: Jan Beulich <jbeulich@suse.com>

Jan



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Re: [PATCH 4/4] x86/boot: Link opt_dom0_verbose to CONFIG_VERBOSE_DEBUG

[Jan Beulich]

>>> On 20.05.19 at 12:18, <andrew.cooper3@citrix.com> wrote:
> We currently have an asymmetric setup where CONFIG_VERBOSE_DEBUG controls
> extra diagnostics for a PV dom0, and opt_dom0_verbose controls extra
> diagnostics for a PVH dom0.
> 
> Default opt_dom0_verbose to CONFIG_VERBOSE_DEBUG and use opt_dom0_verbose
> consistently.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Reviewed-by: Jan Beulich <jbeulich@suse.com>



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Re: [Xen-devel] [PATCH 4/4] x86/boot: Link opt_dom0_verbose to CONFIG_VERBOSE_DEBUG

[Jan Beulich]

>>> On 20.05.19 at 12:18, <andrew.cooper3@citrix.com> wrote:
> We currently have an asymmetric setup where CONFIG_VERBOSE_DEBUG controls
> extra diagnostics for a PV dom0, and opt_dom0_verbose controls extra
> diagnostics for a PVH dom0.
> 
> Default opt_dom0_verbose to CONFIG_VERBOSE_DEBUG and use opt_dom0_verbose
> consistently.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Reviewed-by: Jan Beulich <jbeulich@suse.com>



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