aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorIan Munsie <imunsie@au1.ibm.com>2012-12-03 18:36:13 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2013-01-10 17:00:42 +1100
commita413f474a0ff29404bf1af5c024215476ed6ca01 (patch)
treed147d35ef9f846167738e5a9ca2964353634330a
parent96f013fe1b0904ee9059aa5105f7aa4959cd3914 (diff)
downloadlinaro-lsk-a413f474a0ff29404bf1af5c024215476ed6ca01.tar.gz
powerpc: Disable relocation on exceptions whenever PR KVM is active
For PR KVM we allow userspace to map 0xc000000000000000. Because transitioning from userspace to the guest kernel may use the relocated exception vectors we have to disable relocation on exceptions whenever PR KVM is active as we cannot trust that address. This issue does not apply to HV KVM, since changing from a guest to the hypervisor will never use the relocated exception vectors. Currently the hypervisor interface only allows us to toggle relocation on exceptions on a partition wide scope, so we need to globally disable relocation on exceptions when the first PR KVM instance is started and only re-enable them when all PR KVM instances have been destroyed. It's a bit heavy handed, but until the hypervisor gives us a lightweight way to toggle relocation on exceptions on a single thread it's only real option. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
-rw-r--r--arch/powerpc/include/asm/hvcall.h9
-rw-r--r--arch/powerpc/kvm/book3s_pr.c18
-rw-r--r--arch/powerpc/platforms/pseries/setup.c8
3 files changed, 32 insertions, 3 deletions
diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
index 0975e5c0bb1..4bc2c3dad6a 100644
--- a/arch/powerpc/include/asm/hvcall.h
+++ b/arch/powerpc/include/asm/hvcall.h
@@ -395,6 +395,15 @@ static inline unsigned long cmo_get_page_size(void)
{
return CMO_PageSize;
}
+
+extern long pSeries_enable_reloc_on_exc(void);
+extern long pSeries_disable_reloc_on_exc(void);
+
+#else
+
+#define pSeries_enable_reloc_on_exc() do {} while (0)
+#define pSeries_disable_reloc_on_exc() do {} while (0)
+
#endif /* CONFIG_PPC_PSERIES */
#endif /* __ASSEMBLY__ */
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 28d38adeca7..67e4708388a 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -34,6 +34,7 @@
#include <asm/kvm_book3s.h>
#include <asm/mmu_context.h>
#include <asm/switch_to.h>
+#include <asm/firmware.h>
#include <linux/gfp.h>
#include <linux/sched.h>
#include <linux/vmalloc.h>
@@ -1284,12 +1285,21 @@ void kvmppc_core_flush_memslot(struct kvm *kvm, struct kvm_memory_slot *memslot)
{
}
+static unsigned int kvm_global_user_count = 0;
+static DEFINE_SPINLOCK(kvm_global_user_count_lock);
+
int kvmppc_core_init_vm(struct kvm *kvm)
{
#ifdef CONFIG_PPC64
INIT_LIST_HEAD(&kvm->arch.spapr_tce_tables);
#endif
+ if (firmware_has_feature(FW_FEATURE_SET_MODE)) {
+ spin_lock(&kvm_global_user_count_lock);
+ if (++kvm_global_user_count == 1)
+ pSeries_disable_reloc_on_exc();
+ spin_unlock(&kvm_global_user_count_lock);
+ }
return 0;
}
@@ -1298,6 +1308,14 @@ void kvmppc_core_destroy_vm(struct kvm *kvm)
#ifdef CONFIG_PPC64
WARN_ON(!list_empty(&kvm->arch.spapr_tce_tables));
#endif
+
+ if (firmware_has_feature(FW_FEATURE_SET_MODE)) {
+ spin_lock(&kvm_global_user_count_lock);
+ BUG_ON(kvm_global_user_count == 0);
+ if (--kvm_global_user_count == 0)
+ pSeries_enable_reloc_on_exc();
+ spin_unlock(&kvm_global_user_count_lock);
+ }
}
static int kvmppc_book3s_init(void)
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index ca55882465d..1890730354b 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -375,7 +375,7 @@ static void pSeries_idle(void)
* to ever be a problem in practice we can move this into a kernel thread to
* finish off the process later in boot.
*/
-static int __init pSeries_enable_reloc_on_exc(void)
+long pSeries_enable_reloc_on_exc(void)
{
long rc;
unsigned int delay, total_delay = 0;
@@ -397,9 +397,9 @@ static int __init pSeries_enable_reloc_on_exc(void)
mdelay(delay);
}
}
+EXPORT_SYMBOL(pSeries_enable_reloc_on_exc);
-#ifdef CONFIG_KEXEC
-static long pSeries_disable_reloc_on_exc(void)
+long pSeries_disable_reloc_on_exc(void)
{
long rc;
@@ -410,7 +410,9 @@ static long pSeries_disable_reloc_on_exc(void)
mdelay(get_longbusy_msecs(rc));
}
}
+EXPORT_SYMBOL(pSeries_disable_reloc_on_exc);
+#ifdef CONFIG_KEXEC
static void pSeries_machine_kexec(struct kimage *image)
{
long rc;