[XEN PATCH v1 2/3] x86/hvm: introduce config option for stdvga emulation

[Sergiy Kibrik <Sergiy_Kibrik@xxxxxxxx>]

Introduce config option X86_STDVGA so that stdvga emulation driver can later be
made configurable and be disabled on systems that don't need it.

As a first step the option is hidden from user. No functional changes intended.

Signed-off-by: Sergiy Kibrik <Sergiy_Kibrik@xxxxxxxx>
CC: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/Kconfig              | 3 +++
 xen/arch/x86/hvm/Makefile         | 2 +-
 xen/arch/x86/include/asm/domain.h | 3 ++-
 xen/arch/x86/include/asm/hvm/io.h | 4 ++++
 4 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index 95275dc17e..89c42ff6da 100644
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -147,6 +147,9 @@ config INTEL_VMX
 config X86_PMTIMER
        def_bool HVM
 
+config X86_STDVGA
+       def_bool HVM
+
 config XEN_SHSTK
        bool "Supervisor Shadow Stacks"
        depends on HAS_AS_CET_SS
diff --git a/xen/arch/x86/hvm/Makefile b/xen/arch/x86/hvm/Makefile
index 321241f0bf..b7741b0f60 100644
--- a/xen/arch/x86/hvm/Makefile
+++ b/xen/arch/x86/hvm/Makefile
@@ -22,7 +22,7 @@ obj-$(CONFIG_X86_PMTIMER) += pmtimer.o
 obj-y += quirks.o
 obj-y += rtc.o
 obj-y += save.o
-obj-y += stdvga.o
+obj-$(CONFIG_X86_STDVGA) += stdvga.o
 obj-y += vioapic.o
 obj-y += vlapic.o
 obj-y += vm_event.o
diff --git a/xen/arch/x86/include/asm/domain.h 
b/xen/arch/x86/include/asm/domain.h
index 3f65bfd190..675a13d917 100644
--- a/xen/arch/x86/include/asm/domain.h
+++ b/xen/arch/x86/include/asm/domain.h
@@ -501,7 +501,8 @@ struct arch_domain
 #define has_vrtc(d)        (!!((d)->arch.emulation_flags & X86_EMU_RTC))
 #define has_vioapic(d)     (!!((d)->arch.emulation_flags & X86_EMU_IOAPIC))
 #define has_vpic(d)        (!!((d)->arch.emulation_flags & X86_EMU_PIC))
-#define has_vvga(d)        (!!((d)->arch.emulation_flags & X86_EMU_VGA))
+#define has_vvga(d)        (IS_ENABLED(CONFIG_X86_STDVGA) && \
+                            !!((d)->arch.emulation_flags & X86_EMU_VGA))
 #define has_viommu(d)      (!!((d)->arch.emulation_flags & X86_EMU_IOMMU))
 #define has_vpit(d)        (!!((d)->arch.emulation_flags & X86_EMU_PIT))
 #define has_pirq(d)        (!!((d)->arch.emulation_flags & X86_EMU_USE_PIRQ))
diff --git a/xen/arch/x86/include/asm/hvm/io.h 
b/xen/arch/x86/include/asm/hvm/io.h
index f2b8431fac..32a2490fbc 100644
--- a/xen/arch/x86/include/asm/hvm/io.h
+++ b/xen/arch/x86/include/asm/hvm/io.h
@@ -108,7 +108,11 @@ struct vpci_arch_msix_entry {
     int pirq;
 };
 
+#ifdef CONFIG_X86_STDVGA
 void stdvga_init(struct domain *d);
+#else
+static inline void stdvga_init(struct domain *d) {}
+#endif
 
 extern void hvm_dpci_msi_eoi(struct domain *d, int vector);
 
-- 
2.25.1