[PATCH 3/3] qemu-kvm: add support for gbpages to kvm userspace

[Joerg Roedel <joerg.roedel@xxxxxxx>]

This patch adds a command line parameter to expose the gbpages cpuid bit to the
guest if the kvm kernel module supports it.

Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
---
 qemu-kvm.c           |    1 +
 qemu-kvm.h           |    1 +
 qemu-options.hx      |    2 ++
 target-i386/helper.c |    3 +++
 vl.c                 |    4 ++++
 5 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/qemu-kvm.c b/qemu-kvm.c
index 2aeb17c..01a889d 100644
--- a/qemu-kvm.c
+++ b/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_gbpages = 0;
 kvm_context_t kvm_context;
 
 pthread_mutex_t qemu_mutex = PTHREAD_MUTEX_INITIALIZER;
diff --git a/qemu-kvm.h b/qemu-kvm.h
index fa40542..fc06b96 100644
--- a/qemu-kvm.h
+++ b/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_gbpages;
 extern kvm_context_t kvm_context;
 
 struct ioperm_data {
diff --git a/qemu-options.hx b/qemu-options.hx
index edd99db..fe9e9d3 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1594,6 +1594,8 @@ 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-gbpages", 0, QEMU_OPTION_enable_gbpages,
+    "-enable-gbpages enable support for 1GB pages in the guest (if supported)\n")
 DEF("nvram", HAS_ARG, QEMU_OPTION_nvram,
     "-nvram FILE          provide ia64 nvram contents\n")
 DEF("tdf", 0, QEMU_OPTION_tdf,
diff --git a/target-i386/helper.c b/target-i386/helper.c
index 6dc0111..9fb2ae4 100644
--- a/target-i386/helper.c
+++ b/target-i386/helper.c
@@ -1607,6 +1607,9 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
                 *ecx &= ~4UL;
             /* 3dnow */
             *edx &= ~0xc0000000;
+	    /* enable gbpages and let kvm disable it if unsupported */
+	    if (kvm_gbpages)
+		    *edx |= (1UL << 26UL);
         }
         break;
     case 0x80000002:
diff --git a/vl.c b/vl.c
index 845ed54..262ff1b 100644
--- a/vl.c
+++ b/vl.c
@@ -5621,6 +5621,10 @@ int main(int argc, char **argv, char **envp)
 		kvm_nested = 1;
 		break;
 	    }
+	    case QEMU_OPTION_enable_gbpages: {
+		kvm_gbpages = 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) {
-- 
1.6.3.1


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