[ 09/45] ARM: KVM: perform save/restore of PAR
From: Greg Kroah-Hartman
Date: Sun Aug 18 2013 - 16:37:42 EST
3.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Marc Zyngier <marc.zyngier@xxxxxxx>
commit 6a077e4ab9cbfbf279fb955bae05b03781c97013 upstream.
Not saving PAR is an unfortunate oversight. If the guest performs
an AT* operation and gets scheduled out before reading the result
of the translation from PAR, it could become corrupted by another
guest or the host.
Saving this register is made slightly more complicated as KVM also
uses it on the permission fault handling path, leading to an ugly
"stash and restore" sequence. Fortunately, this is already a slow
path so we don't really care. Also, Linux doesn't do any AT*
operation, so Linux guests are not impacted by this bug.
[ Slightly tweaked to use an even register as first operand to ldrd
and strd operations in interrupts_head.S - Christoffer ]
Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Jonghwan Choi <jhbird.choi@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/include/asm/kvm_asm.h | 22 ++++++++++++----------
arch/arm/kvm/coproc.c | 4 ++++
arch/arm/kvm/interrupts.S | 12 +++++++++++-
arch/arm/kvm/interrupts_head.S | 10 ++++++++--
4 files changed, 35 insertions(+), 13 deletions(-)
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -37,16 +37,18 @@
#define c5_AIFSR 15 /* Auxilary Instrunction Fault Status R */
#define c6_DFAR 16 /* Data Fault Address Register */
#define c6_IFAR 17 /* Instruction Fault Address Register */
-#define c9_L2CTLR 18 /* Cortex A15 L2 Control Register */
-#define c10_PRRR 19 /* Primary Region Remap Register */
-#define c10_NMRR 20 /* Normal Memory Remap Register */
-#define c12_VBAR 21 /* Vector Base Address Register */
-#define c13_CID 22 /* Context ID Register */
-#define c13_TID_URW 23 /* Thread ID, User R/W */
-#define c13_TID_URO 24 /* Thread ID, User R/O */
-#define c13_TID_PRIV 25 /* Thread ID, Privileged */
-#define c14_CNTKCTL 26 /* Timer Control Register (PL1) */
-#define NR_CP15_REGS 27 /* Number of regs (incl. invalid) */
+#define c7_PAR 18 /* Physical Address Register */
+#define c7_PAR_high 19 /* PAR top 32 bits */
+#define c9_L2CTLR 20 /* Cortex A15 L2 Control Register */
+#define c10_PRRR 21 /* Primary Region Remap Register */
+#define c10_NMRR 22 /* Normal Memory Remap Register */
+#define c12_VBAR 23 /* Vector Base Address Register */
+#define c13_CID 24 /* Context ID Register */
+#define c13_TID_URW 25 /* Thread ID, User R/W */
+#define c13_TID_URO 26 /* Thread ID, User R/O */
+#define c13_TID_PRIV 27 /* Thread ID, Privileged */
+#define c14_CNTKCTL 28 /* Timer Control Register (PL1) */
+#define NR_CP15_REGS 29 /* Number of regs (incl. invalid) */
#define ARM_EXCEPTION_RESET 0
#define ARM_EXCEPTION_UNDEFINED 1
--- a/arch/arm/kvm/coproc.c
+++ b/arch/arm/kvm/coproc.c
@@ -180,6 +180,10 @@ static const struct coproc_reg cp15_regs
NULL, reset_unknown, c6_DFAR },
{ CRn( 6), CRm( 0), Op1( 0), Op2( 2), is32,
NULL, reset_unknown, c6_IFAR },
+
+ /* PAR swapped by interrupt.S */
+ { CRn( 7), Op1( 0), is64, NULL, reset_unknown64, c7_PAR },
+
/*
* DC{C,I,CI}SW operations:
*/
--- a/arch/arm/kvm/interrupts.S
+++ b/arch/arm/kvm/interrupts.S
@@ -414,6 +414,10 @@ guest_trap:
mrcne p15, 4, r2, c6, c0, 4 @ HPFAR
bne 3f
+ /* Preserve PAR */
+ mrrc p15, 0, r0, r1, c7 @ PAR
+ push {r0, r1}
+
/* Resolve IPA using the xFAR */
mcr p15, 0, r2, c7, c8, 0 @ ATS1CPR
isb
@@ -424,13 +428,19 @@ guest_trap:
lsl r2, r2, #4
orr r2, r2, r1, lsl #24
+ /* Restore PAR */
+ pop {r0, r1}
+ mcrr p15, 0, r0, r1, c7 @ PAR
+
3: load_vcpu @ Load VCPU pointer to r0
str r2, [r0, #VCPU_HPFAR]
1: mov r1, #ARM_EXCEPTION_HVC
b __kvm_vcpu_return
-4: pop {r0, r1, r2} @ Failed translation, return to guest
+4: pop {r0, r1} @ Failed translation, return to guest
+ mcrr p15, 0, r0, r1, c7 @ PAR
+ pop {r0, r1, r2}
eret
/*
--- a/arch/arm/kvm/interrupts_head.S
+++ b/arch/arm/kvm/interrupts_head.S
@@ -302,11 +302,14 @@ vcpu .req r0 @ vcpu pointer always in r
.endif
mrc p15, 0, r2, c14, c1, 0 @ CNTKCTL
+ mrrc p15, 0, r4, r5, c7 @ PAR
.if \store_to_vcpu == 0
- push {r2}
+ push {r2,r4-r5}
.else
str r2, [vcpu, #CP15_OFFSET(c14_CNTKCTL)]
+ add r12, vcpu, #CP15_OFFSET(c7_PAR)
+ strd r4, r5, [r12]
.endif
.endm
@@ -319,12 +322,15 @@ vcpu .req r0 @ vcpu pointer always in r
*/
.macro write_cp15_state read_from_vcpu
.if \read_from_vcpu == 0
- pop {r2}
+ pop {r2,r4-r5}
.else
ldr r2, [vcpu, #CP15_OFFSET(c14_CNTKCTL)]
+ add r12, vcpu, #CP15_OFFSET(c7_PAR)
+ ldrd r4, r5, [r12]
.endif
mcr p15, 0, r2, c14, c1, 0 @ CNTKCTL
+ mcrr p15, 0, r4, r5, c7 @ PAR
.if \read_from_vcpu == 0
pop {r2-r12}
--
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