This is a note to let you know that I've just added the patch titled
arm64: KVM: Do not use pgd_index to index stage-2 pgd
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm64-kvm-do-not-use-pgd_index-to-index-stage-2-pgd.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 04b8dc85bf4a64517e3cf20e409eeaa503b15cc1 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <marc.zyngier@xxxxxxx>
Date: Tue, 10 Mar 2015 19:07:00 +0000
Subject: arm64: KVM: Do not use pgd_index to index stage-2 pgd
From: Marc Zyngier <marc.zyngier@xxxxxxx>
commit 04b8dc85bf4a64517e3cf20e409eeaa503b15cc1 upstream.
[Since we don't backport commit c647355 (KVM: arm: Add initial dirty page
locking support) for linux-3.14.y, there is no stage2_wp_range in
arch/arm/kvm/mmu.c. So ignore the change in stage2_wp_range introduced
by this patch.]
The kernel's pgd_index macro is designed to index a normal, page
sized array. KVM is a bit diffferent, as we can use concatenated
pages to have a bigger address space (for example 40bit IPA with
4kB pages gives us an 8kB PGD.
In the above case, the use of pgd_index will always return an index
inside the first 4kB, which makes a guest that has memory above
0x8000000000 rather unhappy, as it spins forever in a page fault,
whist the host happilly corrupts the lower pgd.
The obvious fix is to get our own kvm_pgd_index that does the right
thing(tm).
Tested on X-Gene with a hacked kvmtool that put memory at a stupidly
high address.
Reviewed-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/include/asm/kvm_mmu.h | 3 ++-
arch/arm/kvm/mmu.c | 6 +++---
arch/arm64/include/asm/kvm_mmu.h | 2 ++
3 files changed, 7 insertions(+), 4 deletions(-)
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -117,13 +117,14 @@ static inline void kvm_set_s2pmd_writabl
(__boundary - 1 < (end) - 1)? __boundary: (end); \
})
+#define kvm_pgd_index(addr) pgd_index(addr)
+
static inline bool kvm_page_empty(void *ptr)
{
struct page *ptr_page = virt_to_page(ptr);
return page_count(ptr_page) == 1;
}
-
#define kvm_pte_table_empty(ptep) kvm_page_empty(ptep)
#define kvm_pmd_table_empty(pmdp) kvm_page_empty(pmdp)
#define kvm_pud_table_empty(pudp) (0)
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -194,7 +194,7 @@ static void unmap_range(struct kvm *kvm,
phys_addr_t addr = start, end = start + size;
phys_addr_t next;
- pgd = pgdp + pgd_index(addr);
+ pgd = pgdp + kvm_pgd_index(addr);
do {
next = kvm_pgd_addr_end(addr, end);
if (!pgd_none(*pgd))
@@ -264,7 +264,7 @@ static void stage2_flush_memslot(struct
phys_addr_t next;
pgd_t *pgd;
- pgd = kvm->arch.pgd + pgd_index(addr);
+ pgd = kvm->arch.pgd + kvm_pgd_index(addr);
do {
next = kvm_pgd_addr_end(addr, end);
stage2_flush_puds(kvm, pgd, addr, next);
@@ -649,7 +649,7 @@ static pmd_t *stage2_get_pmd(struct kvm
pud_t *pud;
pmd_t *pmd;
- pgd = kvm->arch.pgd + pgd_index(addr);
+ pgd = kvm->arch.pgd + kvm_pgd_index(addr);
pud = pud_offset(pgd, addr);
if (pud_none(*pud)) {
if (!cache)
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -69,6 +69,8 @@
#define PTRS_PER_S2_PGD (1 << (KVM_PHYS_SHIFT - PGDIR_SHIFT))
#define S2_PGD_ORDER get_order(PTRS_PER_S2_PGD * sizeof(pgd_t))
+#define kvm_pgd_index(addr) (((addr) >> PGDIR_SHIFT) & (PTRS_PER_S2_PGD - 1))
+
int create_hyp_mappings(void *from, void *to);
int create_hyp_io_mappings(void *from, void *to, phys_addr_t);
void free_boot_hyp_pgd(void);
Patches currently in stable-queue which might be from marc.zyngier@xxxxxxx are
queue-3.14/arm64-kvm-fix-hcr-setting-for-32bit-guests.patch
queue-3.14/arm64-kvm-do-not-use-pgd_index-to-index-stage-2-pgd.patch
queue-3.14/arm64-kvm-fix-tlb-invalidation-by-ipa-vmid.patch
queue-3.14/arm-arm64-kvm-keep-elrsr-aisr-in-sync-with-software-model.patch
queue-3.14/arm-arm64-kvm-require-in-kernel-vgic-for-the-arch-timers.patch
queue-3.14/arm-kvm-force-execution-of-hcptr-access-on-vm-exit.patch
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