[PATCH] kvm/qemu: set gbpages cpuid bit if kvm supports it

[Joerg Roedel <joerg.roedel@xxxxxxx>]

This patch contains the userspace part necessary to make use of the KVM
1GB page support.

Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
---
 libkvm/libkvm.c           |    9 +++++++++
 libkvm/libkvm.h           |    1 +
 qemu/qemu-kvm.c           |    6 ++++++
 qemu/qemu-kvm.h           |    3 +++
 qemu/qemu-options.hx      |    2 ++
 qemu/target-i386/helper.c |    4 ++++
 qemu/vl.c                 |    4 ++++
 7 files changed, 29 insertions(+), 0 deletions(-)

diff --git a/libkvm/libkvm.c b/libkvm/libkvm.c
index 0610e3f..a699fe9 100644
--- a/libkvm/libkvm.c
+++ b/libkvm/libkvm.c
@@ -1065,6 +1065,15 @@ int kvm_has_sync_mmu(kvm_context_t kvm)
         return r;
 }
 
+int kvm_has_gbpages(kvm_context_t kvm)
+{
+	int r = 0;
+#ifdef KVM_CAP_1GB_PAGES
+	r = ioctl(kvm->fd, KVM_CHECK_EXTENSION, KVM_CAP_1GB_PAGES);
+#endif
+	return r;
+}
+
 int kvm_inject_nmi(kvm_context_t kvm, int vcpu)
 {
 #ifdef KVM_CAP_USER_NMI
diff --git a/libkvm/libkvm.h b/libkvm/libkvm.h
index d3e431a..efbc23e 100644
--- a/libkvm/libkvm.h
+++ b/libkvm/libkvm.h
@@ -558,6 +558,7 @@ int kvm_dirty_pages_log_reset(kvm_context_t kvm);
 int kvm_irqchip_in_kernel(kvm_context_t kvm);
 
 int kvm_has_sync_mmu(kvm_context_t kvm);
+int kvm_has_gbpages(kvm_context_t kvm);
 
 #ifdef KVM_CAP_IRQCHIP
 /*!
diff --git a/qemu/qemu-kvm.c b/qemu/qemu-kvm.c
index ed76367..bae0639 100644
--- a/qemu/qemu-kvm.c
+++ b/qemu/qemu-kvm.c
@@ -33,6 +33,7 @@ int kvm_irqchip = 1;
 int kvm_pit = 1;
 int kvm_pit_reinject = 1;
 int kvm_nested = 0;
+int kvm_gb_pages = 0;
 kvm_context_t kvm_context;
 
 pthread_mutex_t qemu_mutex = PTHREAD_MUTEX_INITIALIZER;
@@ -1401,6 +1402,11 @@ int qemu_kvm_has_sync_mmu(void)
     return kvm_has_sync_mmu(kvm_context);
 }
 
+int qemu_kvm_has_gbpages()
+{
+	return kvm_has_gbpages(kvm_context);
+}
+
 void qemu_kvm_cpu_stop(CPUState *env)
 {
     if (kvm_enabled())
diff --git a/qemu/qemu-kvm.h b/qemu/qemu-kvm.h
index ca59af8..6f2d99f 100644
--- a/qemu/qemu-kvm.h
+++ b/qemu/qemu-kvm.h
@@ -151,6 +151,7 @@ extern int kvm_irqchip;
 extern int kvm_pit;
 extern int kvm_pit_reinject;
 extern int kvm_nested;
+extern int kvm_gb_pages;
 extern kvm_context_t kvm_context;
 
 struct ioperm_data {
@@ -161,6 +162,7 @@ struct ioperm_data {
 };
 
 int qemu_kvm_has_sync_mmu(void);
+int qemu_kvm_has_gbpages(void);
 void qemu_kvm_cpu_stop(CPUState *env);
 
 #define kvm_enabled() (kvm_allowed)
@@ -172,6 +174,7 @@ void kvm_load_tsc(CPUState *env);
 #else
 #define kvm_enabled() (0)
 #define kvm_nested 0
+#define kvm_gb_pages 0
 #define qemu_kvm_irqchip_in_kernel() (0)
 #define qemu_kvm_pit_in_kernel() (0)
 #define kvm_has_sync_mmu() (0)
diff --git a/qemu/qemu-options.hx b/qemu/qemu-options.hx
index ba7f291..ccc1769 100644
--- a/qemu/qemu-options.hx
+++ b/qemu/qemu-options.hx
@@ -1490,6 +1490,8 @@ DEF("pcidevice", HAS_ARG, QEMU_OPTION_pcidevice,
 #endif
 DEF("enable-nesting", 0, QEMU_OPTION_enable_nesting,
     "-enable-nesting enable support for running a VM inside the VM (AMD only)\n")
+DEF("enable-gb-pages", 0, QEMU_OPTION_enable_gb_pages,
+    "-enable-gb-pages enable GB pages in the guest (if host supports it)\n")
 DEF("cpu-vendor", HAS_ARG, QEMU_OPTION_cpu_vendor,
     "-cpu-vendor STRING   override the cpuid vendor string\n")
 DEF("nvram", HAS_ARG, QEMU_OPTION_nvram,
diff --git a/qemu/target-i386/helper.c b/qemu/target-i386/helper.c
index be7b021..78a5db5 100644
--- a/qemu/target-i386/helper.c
+++ b/qemu/target-i386/helper.c
@@ -1585,6 +1585,10 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
                 *ecx &= ~4UL;
             /* 3dnow */
             *edx &= ~0xc0000000;
+#ifdef USE_KVM
+            if (qemu_kvm_has_gbpages() && kvm_gb_pages)
+                *edx |= CPUID_EXT2_PDPE1GB;
+#endif
         }
         break;
     case 0x80000002:
diff --git a/qemu/vl.c b/qemu/vl.c
index 8aa9ebc..ac28fc4 100644
--- a/qemu/vl.c
+++ b/qemu/vl.c
@@ -5024,6 +5024,10 @@ int main(int argc, char **argv, char **envp)
 		kvm_nested = 1;
 		break;
 	    }
+            case QEMU_OPTION_enable_gb_pages: {
+                kvm_gb_pages = 1;
+		break;
+            }
 #if defined(TARGET_I386) || defined(TARGET_X86_64) || defined(TARGET_IA64) || defined(__linux__)
             case QEMU_OPTION_pcidevice:
 		if (assigned_devices_index >= MAX_DEV_ASSIGN_CMDLINE) {
-- 
1.6.2.3


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