[PATCH 3.14 46/51] ARM: KVM: add world-switch for AMAIR{0,1}

Greg Kroah-Hartman
2015-05-15T23:11:44Z

From: Marc Zyngier <marc.zyngier@arm.com>

commit af20814ee927ed888288d98917a766b4179c4fe0 upstream.

HCR.TVM traps (among other things) accesses to AMAIR0 and AMAIR1.
In order to minimise the amount of surprise a guest could generate by
trying to access these registers with caches off, add them to the
list of registers we switch/handle.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Shannon Zhao <shannon.zhao@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/arm/include/asm/kvm_asm.h | 4 +++-
arch/arm/kvm/coproc.c | 6 ++++++
arch/arm/kvm/interrupts_head.S | 12 ++++++++++--
3 files changed, 19 insertions(+), 3 deletions(-)

--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -48,7 +48,9 @@
#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 c10_AMAIR0 29 /* Auxilary Memory Attribute Indirection Reg0 */
+#define c10_AMAIR1 30 /* Auxilary Memory Attribute Indirection Reg1 */
+#define NR_CP15_REGS 31 /* 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
@@ -328,6 +328,12 @@ static const struct coproc_reg cp15_regs
{ CRn(10), CRm( 2), Op1( 0), Op2( 1), is32,
NULL, reset_unknown, c10_NMRR},

+ /* AMAIR0/AMAIR1: swapped by interrupt.S. */
+ { CRn(10), CRm( 3), Op1( 0), Op2( 0), is32,
+ access_vm_reg, reset_unknown, c10_AMAIR0},
+ { CRn(10), CRm( 3), Op1( 0), Op2( 1), is32,
+ access_vm_reg, reset_unknown, c10_AMAIR1},
+
/* VBAR: swapped by interrupt.S. */
{ CRn(12), CRm( 0), Op1( 0), Op2( 0), is32,
NULL, reset_val, c12_VBAR, 0x00000000 },
--- a/arch/arm/kvm/interrupts_head.S
+++ b/arch/arm/kvm/interrupts_head.S
@@ -303,13 +303,17 @@ vcpu .req r0 @ vcpu pointer always in r

mrc p15, 0, r2, c14, c1, 0 @ CNTKCTL
mrrc p15, 0, r4, r5, c7 @ PAR
+ mrc p15, 0, r6, c10, c3, 0 @ AMAIR0
+ mrc p15, 0, r7, c10, c3, 1 @ AMAIR1

.if \store_to_vcpu == 0
- push {r2,r4-r5}
+ push {r2,r4-r7}
.else
str r2, [vcpu, #CP15_OFFSET(c14_CNTKCTL)]
add r12, vcpu, #CP15_OFFSET(c7_PAR)
strd r4, r5, [r12]
+ str r6, [vcpu, #CP15_OFFSET(c10_AMAIR0)]
+ str r7, [vcpu, #CP15_OFFSET(c10_AMAIR1)]
.endif
.endm

@@ -322,15 +326,19 @@ vcpu .req r0 @ vcpu pointer always in r
*/
.macro write_cp15_state read_from_vcpu
.if \read_from_vcpu == 0
- pop {r2,r4-r5}
+ pop {r2,r4-r7}
.else
ldr r2, [vcpu, #CP15_OFFSET(c14_CNTKCTL)]
add r12, vcpu, #CP15_OFFSET(c7_PAR)
ldrd r4, r5, [r12]
+ ldr r6, [vcpu, #CP15_OFFSET(c10_AMAIR0)]
+ ldr r7, [vcpu, #CP15_OFFSET(c10_AMAIR1)]
.endif

mcr p15, 0, r2, c14, c1, 0 @ CNTKCTL
mcrr p15, 0, r4, r5, c7 @ PAR
+ mcr p15, 0, r6, c10, c3, 0 @ AMAIR0
+ mcr p15, 0, r7, c10, c3, 1 @ AMAIR1

.if \read_from_vcpu == 0
pop {r2-r12}