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authorAnshuman Khandual <khandual@linux.vnet.ibm.com>2019-08-20 05:13:18 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2019-08-30 02:55:40 +0300
commitbd104e6db6f0ad124e507a9ecf1a468efe5697db (patch)
treea7add55ca321c68c3116de09762d567b9b7786f0 /arch/powerpc/kernel/paca.c
parente311a92da18cbdd4972dab0cda88b1b8484b8fef (diff)
downloadlinux-bd104e6db6f0ad124e507a9ecf1a468efe5697db.tar.xz
powerpc/pseries/svm: Use shared memory for LPPACA structures
LPPACA structures need to be shared with the host. Hence they need to be in shared memory. Instead of allocating individual chunks of memory for a given structure from memblock, a contiguous chunk of memory is allocated and then converted into shared memory. Subsequent allocation requests will come from the contiguous chunk which will be always shared memory for all structures. While we are able to use a kmem_cache constructor for the Debug Trace Log, LPPACAs are allocated very early in the boot process (before SLUB is available) so we need to use a simpler scheme here. Introduce helper is_svm_platform() which uses the S bit of the MSR to tell whether we're running as a secure guest. Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20190820021326.6884-9-bauerman@linux.ibm.com
Diffstat (limited to 'arch/powerpc/kernel/paca.c')
-rw-r--r--arch/powerpc/kernel/paca.c43
1 files changed, 42 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index 612fc87ef785..949eceb254d8 100644
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -14,6 +14,8 @@
#include <asm/sections.h>
#include <asm/pgtable.h>
#include <asm/kexec.h>
+#include <asm/svm.h>
+#include <asm/ultravisor.h>
#include "setup.h"
@@ -54,6 +56,41 @@ static void *__init alloc_paca_data(unsigned long size, unsigned long align,
#define LPPACA_SIZE 0x400
+static void *__init alloc_shared_lppaca(unsigned long size, unsigned long align,
+ unsigned long limit, int cpu)
+{
+ size_t shared_lppaca_total_size = PAGE_ALIGN(nr_cpu_ids * LPPACA_SIZE);
+ static unsigned long shared_lppaca_size;
+ static void *shared_lppaca;
+ void *ptr;
+
+ if (!shared_lppaca) {
+ memblock_set_bottom_up(true);
+
+ shared_lppaca =
+ memblock_alloc_try_nid(shared_lppaca_total_size,
+ PAGE_SIZE, MEMBLOCK_LOW_LIMIT,
+ limit, NUMA_NO_NODE);
+ if (!shared_lppaca)
+ panic("cannot allocate shared data");
+
+ memblock_set_bottom_up(false);
+ uv_share_page(PHYS_PFN(__pa(shared_lppaca)),
+ shared_lppaca_total_size >> PAGE_SHIFT);
+ }
+
+ ptr = shared_lppaca + shared_lppaca_size;
+ shared_lppaca_size += size;
+
+ /*
+ * This is very early in boot, so no harm done if the kernel crashes at
+ * this point.
+ */
+ BUG_ON(shared_lppaca_size >= shared_lppaca_total_size);
+
+ return ptr;
+}
+
/*
* See asm/lppaca.h for more detail.
*
@@ -83,7 +120,11 @@ static struct lppaca * __init new_lppaca(int cpu, unsigned long limit)
if (early_cpu_has_feature(CPU_FTR_HVMODE))
return NULL;
- lp = alloc_paca_data(LPPACA_SIZE, 0x400, limit, cpu);
+ if (is_secure_guest())
+ lp = alloc_shared_lppaca(LPPACA_SIZE, 0x400, limit, cpu);
+ else
+ lp = alloc_paca_data(LPPACA_SIZE, 0x400, limit, cpu);
+
init_lppaca(lp);
return lp;