From 921fa4d670d801e9394f843dd14e2d7faabbba4a Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 21 Jun 2013 13:08:46 +0100 Subject: ARM: KVM: perform save/restore of PAR 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 Signed-off-by: Christoffer Dall Signed-off-by: Jonghwan Choi Signed-off-by: Greg Kroah-Hartman --- 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(-) diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h index 18d50322a9e2..4bb08e3e52bc 100644 --- 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 diff --git a/arch/arm/kvm/coproc.c b/arch/arm/kvm/coproc.c index 8eea97be1ed5..4a5199070430 100644 --- 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: */ diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S index f7793df62f58..d0a8fa33409a 100644 --- 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 /* diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S index 3c8f2f0b4c5e..2b44b95a86dd 100644 --- 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 r0 .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 r0 */ .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} -- cgit v1.2.3