[PATCH 34/36] x86/domain: implement domain_has_vuart()

[Denis Mukhin via B4 Relay <devnull+dmukhin.ford.com@xxxxxxxxxx>]

From: Denis Mukhin <dmukhin@xxxxxxxx>

Add new emulation flag for virtual UART on x86 and plumb it through the stack.

This change enables NS8250 emulator initialization.

Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>
---
 tools/libs/light/libxl_x86.c      |  6 +++++-
 tools/ocaml/libs/xc/xenctrl.ml    |  1 +
 tools/ocaml/libs/xc/xenctrl.mli   |  1 +
 tools/python/xen/lowlevel/xc/xc.c |  4 +---
 xen/arch/x86/domain.c             |  8 +++++---
 xen/arch/x86/include/asm/domain.h |  7 ++++---
 xen/include/public/arch-x86/xen.h | 14 +++++++++++++-
 7 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/tools/libs/light/libxl_x86.c b/tools/libs/light/libxl_x86.c
index 
a3164a3077fec7e1b81a34074894dc646954a49a..de5f05e18cb0671bb031b101b9a7159eb0fe0178
 100644
--- a/tools/libs/light/libxl_x86.c
+++ b/tools/libs/light/libxl_x86.c
@@ -8,7 +8,11 @@ int libxl__arch_domain_prepare_config(libxl__gc *gc,
 {
     switch(d_config->c_info.type) {
     case LIBXL_DOMAIN_TYPE_HVM:
-        config->arch.emulation_flags = (XEN_X86_EMU_ALL & ~XEN_X86_EMU_VPCI);
+        config->arch.emulation_flags = XEN_X86_EMU_ALL;
+        config->arch.emulation_flags &= ~XEN_X86_EMU_VPCI;
+        /* Virtual UART is selected at Xen build time */
+        config->arch.emulation_flags &= ~XEN_X86_EMU_VUART;
+
         if (!libxl_defbool_val(d_config->b_info.u.hvm.pirq))
             config->arch.emulation_flags &= ~XEN_X86_EMU_USE_PIRQ;
         break;
diff --git a/tools/ocaml/libs/xc/xenctrl.ml b/tools/ocaml/libs/xc/xenctrl.ml
index 
2690f9a92316b812ad3d3ff0e1c36823070adb4a..647239b3e55e88b00eb8e9773a5267894cbbae54
 100644
--- a/tools/ocaml/libs/xc/xenctrl.ml
+++ b/tools/ocaml/libs/xc/xenctrl.ml
@@ -47,6 +47,7 @@ type x86_arch_emulation_flags =
   | X86_EMU_PIT
   | X86_EMU_USE_PIRQ
   | X86_EMU_VPCI
+  | X86_EMU_VUART
 
 type x86_arch_misc_flags =
   | X86_MSR_RELAXED
diff --git a/tools/ocaml/libs/xc/xenctrl.mli b/tools/ocaml/libs/xc/xenctrl.mli
index 
febbe1f6ae3f10c5abe45eaa3c06a8a67d9ba268..4f5f64c786e83e8a0c3dd3cdb0460f7095de4a62
 100644
--- a/tools/ocaml/libs/xc/xenctrl.mli
+++ b/tools/ocaml/libs/xc/xenctrl.mli
@@ -41,6 +41,7 @@ type x86_arch_emulation_flags =
   | X86_EMU_PIT
   | X86_EMU_USE_PIRQ
   | X86_EMU_VPCI
+  | X86_EMU_VUART
 
 type x86_arch_misc_flags =
   | X86_MSR_RELAXED
diff --git a/tools/python/xen/lowlevel/xc/xc.c 
b/tools/python/xen/lowlevel/xc/xc.c
index 
9feb12ae2b16e48cb5d0c3c45044ae226f152f2d..e54308956efc7061d58d2166ec9a95bc1dcd1781
 100644
--- a/tools/python/xen/lowlevel/xc/xc.c
+++ b/tools/python/xen/lowlevel/xc/xc.c
@@ -159,9 +159,7 @@ static PyObject *pyxc_domain_create(XcObject *self,
 
 #if defined (__i386) || defined(__x86_64__)
     if ( config.flags & XEN_DOMCTL_CDF_hvm )
-        config.arch.emulation_flags = XEN_X86_EMU_ALL &
-                                      ~(XEN_X86_EMU_VPCI |
-                                        XEN_X86_EMU_USE_PIRQ);
+        config.arch.emulation_flags = XEN_X86_EMU_HVM_ALLOWABLE;
 #elif defined (__arm__) || defined(__aarch64__)
     config.arch.gic_version = XEN_DOMCTL_CONFIG_GIC_NATIVE;
 #else
diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 
c88d422a64544531c1e1058fa484364bb4277d1e..439da7adc92a3a8eb481075bf834da5f9670dd54
 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -752,10 +752,10 @@ static bool emulation_flags_ok(const struct domain *d, 
uint32_t emflags)
         if ( is_hardware_domain(d) &&
              emflags != (X86_EMU_VPCI | X86_EMU_LAPIC | X86_EMU_IOAPIC) )
             return false;
+
+        emflags &= ~X86_EMU_VUART;
         if ( !is_hardware_domain(d) &&
-             /* HVM PIRQ feature is user-selectable. */
-             (emflags & ~X86_EMU_USE_PIRQ) !=
-             (X86_EMU_ALL & ~(X86_EMU_VPCI | X86_EMU_USE_PIRQ)) &&
+             xen_emflags_allowable(emflags) != XEN_X86_EMU_HVM_ALLOWABLE &&
              emflags != X86_EMU_LAPIC )
             return false;
     }
@@ -806,6 +806,8 @@ int arch_domain_create(struct domain *d,
 
     emflags = config->arch.emulation_flags;
 
+    if ( IS_ENABLED(CONFIG_HAS_VUART_NS8250) && is_hvm_domain(d) )
+        emflags |= XEN_X86_EMU_VUART;
     if ( is_hardware_domain(d) && is_pv_domain(d) )
         emflags |= XEN_X86_EMU_PIT;
 
diff --git a/xen/arch/x86/include/asm/domain.h 
b/xen/arch/x86/include/asm/domain.h
index 
c1d0d1f47324e8cc678a4c76c43f86820a89e7b3..dacea6e1aad46e9f8710b2202bb81203c5e92807
 100644
--- a/xen/arch/x86/include/asm/domain.h
+++ b/xen/arch/x86/include/asm/domain.h
@@ -484,7 +484,8 @@ struct arch_domain
 #define X86_EMU_VPCI     0
 #endif
 
-#define X86_EMU_PIT     XEN_X86_EMU_PIT
+#define X86_EMU_PIT      XEN_X86_EMU_PIT
+#define X86_EMU_VUART    XEN_X86_EMU_VUART
 
 /* This must match XEN_X86_EMU_ALL in xen.h */
 #define X86_EMU_ALL             (X86_EMU_LAPIC | X86_EMU_HPET |         \
@@ -492,7 +493,7 @@ struct arch_domain
                                  X86_EMU_IOAPIC | X86_EMU_PIC |         \
                                  X86_EMU_VGA | X86_EMU_IOMMU |          \
                                  X86_EMU_PIT | X86_EMU_USE_PIRQ |       \
-                                 X86_EMU_VPCI)
+                                 X86_EMU_VPCI | X86_EMU_VUART)
 
 #define has_vlapic(d)      (!!((d)->arch.emulation_flags & X86_EMU_LAPIC))
 #define has_vhpet(d)       (!!((d)->arch.emulation_flags & X86_EMU_HPET))
@@ -507,7 +508,7 @@ struct arch_domain
 #define has_vpci(d)        (!!((d)->arch.emulation_flags & X86_EMU_VPCI))
 
 /* NB: same symbol as in Arm port */
-#define domain_has_vuart(d) false
+#define domain_has_vuart(d) (!!((d)->arch.emulation_flags & X86_EMU_VUART))
 
 #define gdt_ldt_pt_idx(v) \
       ((v)->vcpu_id >> (PAGETABLE_ORDER - GDT_LDT_VCPU_SHIFT))
diff --git a/xen/include/public/arch-x86/xen.h 
b/xen/include/public/arch-x86/xen.h
index 
fc2487986642a7694578ab9d2f5f16d09761bff8..e7922e3f9ddc1742a464d228807279839df31e52
 100644
--- a/xen/include/public/arch-x86/xen.h
+++ b/xen/include/public/arch-x86/xen.h
@@ -283,13 +283,25 @@ struct xen_arch_domainconfig {
 #define XEN_X86_EMU_USE_PIRQ        (1U<<_XEN_X86_EMU_USE_PIRQ)
 #define _XEN_X86_EMU_VPCI           10
 #define XEN_X86_EMU_VPCI            (1U<<_XEN_X86_EMU_VPCI)
+#define _XEN_X86_EMU_VUART          11
+#define XEN_X86_EMU_VUART           (1U<<_XEN_X86_EMU_VUART)
 
 #define XEN_X86_EMU_ALL             (XEN_X86_EMU_LAPIC | XEN_X86_EMU_HPET |  \
                                      XEN_X86_EMU_PM | XEN_X86_EMU_RTC |      \
                                      XEN_X86_EMU_IOAPIC | XEN_X86_EMU_PIC |  \
                                      XEN_X86_EMU_VGA | XEN_X86_EMU_IOMMU |   \
                                      XEN_X86_EMU_PIT | XEN_X86_EMU_USE_PIRQ |\
-                                     XEN_X86_EMU_VPCI)
+                                     XEN_X86_EMU_VPCI | XEN_X86_EMU_VUART)
+
+/* HVM PIRQ feature is user-selectable (libxl). */
+#define XEN_X86_EMU_HVM_SELECTABLE  (XEN_X86_EMU_VPCI | \
+                                     XEN_X86_EMU_USE_PIRQ | \
+                                     XEN_X86_EMU_VUART)
+
+#define xen_emflags_allowable(x)    ((x) & ~XEN_X86_EMU_HVM_SELECTABLE)
+
+#define XEN_X86_EMU_HVM_ALLOWABLE   xen_emflags_allowable(XEN_X86_EMU_ALL)
+
     uint32_t emulation_flags;
 
 /*

-- 
2.34.1