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arm/arm64: KVM: Fix BE accesses to GICv2 EISR and ELRSR regs
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The EIRSR and ELRSR registers are 32-bit registers on GICv2, and we
store these as an array of two such registers on the vgic vcpu struct.
However, we access them as a single 64-bit value or as a bitmap pointer
in the generic vgic code, which breaks BE support.

Instead, store them as u64 values on the vgic structure and do the
word-swapping in the assembly code, which already handles the byte order
for BE systems.

Tested-by: Victor Kamensky <[email protected]>
Acked-by: Marc Zyngier <[email protected]>
Signed-off-by: Christoffer Dall <[email protected]>
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chazy committed Oct 16, 2014
1 parent 3d08c62 commit 2df36a5
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Showing 5 changed files with 36 additions and 29 deletions.
7 changes: 7 additions & 0 deletions arch/arm/kvm/interrupts_head.S
Original file line number Diff line number Diff line change
Expand Up @@ -433,10 +433,17 @@ ARM_BE8(rev r10, r10 )
str r3, [r11, #VGIC_V2_CPU_HCR]
str r4, [r11, #VGIC_V2_CPU_VMCR]
str r5, [r11, #VGIC_V2_CPU_MISR]
#ifdef CONFIG_CPU_ENDIAN_BE8
str r6, [r11, #(VGIC_V2_CPU_EISR + 4)]
str r7, [r11, #VGIC_V2_CPU_EISR]
str r8, [r11, #(VGIC_V2_CPU_ELRSR + 4)]
str r9, [r11, #VGIC_V2_CPU_ELRSR]
#else
str r6, [r11, #VGIC_V2_CPU_EISR]
str r7, [r11, #(VGIC_V2_CPU_EISR + 4)]
str r8, [r11, #VGIC_V2_CPU_ELRSR]
str r9, [r11, #(VGIC_V2_CPU_ELRSR + 4)]
#endif
str r10, [r11, #VGIC_V2_CPU_APR]

/* Clear GICH_HCR */
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12 changes: 8 additions & 4 deletions arch/arm64/kvm/vgic-v2-switch.S
Original file line number Diff line number Diff line change
Expand Up @@ -67,10 +67,14 @@ CPU_BE( rev w11, w11 )
str w4, [x3, #VGIC_V2_CPU_HCR]
str w5, [x3, #VGIC_V2_CPU_VMCR]
str w6, [x3, #VGIC_V2_CPU_MISR]
str w7, [x3, #VGIC_V2_CPU_EISR]
str w8, [x3, #(VGIC_V2_CPU_EISR + 4)]
str w9, [x3, #VGIC_V2_CPU_ELRSR]
str w10, [x3, #(VGIC_V2_CPU_ELRSR + 4)]
CPU_LE( str w7, [x3, #VGIC_V2_CPU_EISR] )
CPU_LE( str w8, [x3, #(VGIC_V2_CPU_EISR + 4)] )
CPU_LE( str w9, [x3, #VGIC_V2_CPU_ELRSR] )
CPU_LE( str w10, [x3, #(VGIC_V2_CPU_ELRSR + 4)] )
CPU_BE( str w7, [x3, #(VGIC_V2_CPU_EISR + 4)] )
CPU_BE( str w8, [x3, #VGIC_V2_CPU_EISR] )
CPU_BE( str w9, [x3, #(VGIC_V2_CPU_ELRSR + 4)] )
CPU_BE( str w10, [x3, #VGIC_V2_CPU_ELRSR] )
str w11, [x3, #VGIC_V2_CPU_APR]

/* Clear GICH_HCR */
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4 changes: 2 additions & 2 deletions include/kvm/arm_vgic.h
Original file line number Diff line number Diff line change
Expand Up @@ -219,8 +219,8 @@ struct vgic_v2_cpu_if {
u32 vgic_hcr;
u32 vgic_vmcr;
u32 vgic_misr; /* Saved only */
u32 vgic_eisr[2]; /* Saved only */
u32 vgic_elrsr[2]; /* Saved only */
u64 vgic_eisr; /* Saved only */
u64 vgic_elrsr; /* Saved only */
u32 vgic_apr;
u32 vgic_lr[VGIC_V2_MAX_LRS];
};
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24 changes: 3 additions & 21 deletions virt/kvm/arm/vgic-v2.c
Original file line number Diff line number Diff line change
Expand Up @@ -71,35 +71,17 @@ static void vgic_v2_sync_lr_elrsr(struct kvm_vcpu *vcpu, int lr,
struct vgic_lr lr_desc)
{
if (!(lr_desc.state & LR_STATE_MASK))
set_bit(lr, (unsigned long *)vcpu->arch.vgic_cpu.vgic_v2.vgic_elrsr);
vcpu->arch.vgic_cpu.vgic_v2.vgic_elrsr |= (1ULL << lr);
}

static u64 vgic_v2_get_elrsr(const struct kvm_vcpu *vcpu)
{
u64 val;

#if BITS_PER_LONG == 64
val = vcpu->arch.vgic_cpu.vgic_v2.vgic_elrsr[1];
val <<= 32;
val |= vcpu->arch.vgic_cpu.vgic_v2.vgic_elrsr[0];
#else
val = *(u64 *)vcpu->arch.vgic_cpu.vgic_v2.vgic_elrsr;
#endif
return val;
return vcpu->arch.vgic_cpu.vgic_v2.vgic_elrsr;
}

static u64 vgic_v2_get_eisr(const struct kvm_vcpu *vcpu)
{
u64 val;

#if BITS_PER_LONG == 64
val = vcpu->arch.vgic_cpu.vgic_v2.vgic_eisr[1];
val <<= 32;
val |= vcpu->arch.vgic_cpu.vgic_v2.vgic_eisr[0];
#else
val = *(u64 *)vcpu->arch.vgic_cpu.vgic_v2.vgic_eisr;
#endif
return val;
return vcpu->arch.vgic_cpu.vgic_v2.vgic_eisr;
}

static u32 vgic_v2_get_interrupt_status(const struct kvm_vcpu *vcpu)
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18 changes: 16 additions & 2 deletions virt/kvm/arm/vgic.c
Original file line number Diff line number Diff line change
Expand Up @@ -145,6 +145,20 @@ static void vgic_free_bitmap(struct vgic_bitmap *b)
b->shared = NULL;
}

/*
* Call this function to convert a u64 value to an unsigned long * bitmask
* in a way that works on both 32-bit and 64-bit LE and BE platforms.
*
* Warning: Calling this function may modify *val.
*/
static unsigned long *u64_to_bitmask(u64 *val)
{
#if defined(CONFIG_CPU_BIG_ENDIAN) && BITS_PER_LONG == 32
*val = (*val >> 32) | (*val << 32);
#endif
return (unsigned long *)val;
}

static u32 *vgic_bitmap_get_reg(struct vgic_bitmap *x,
int cpuid, u32 offset)
{
Expand Down Expand Up @@ -1442,7 +1456,7 @@ static bool vgic_process_maintenance(struct kvm_vcpu *vcpu)
* active bit.
*/
u64 eisr = vgic_get_eisr(vcpu);
unsigned long *eisr_ptr = (unsigned long *)&eisr;
unsigned long *eisr_ptr = u64_to_bitmask(&eisr);
int lr;

for_each_set_bit(lr, eisr_ptr, vgic->nr_lr) {
Expand Down Expand Up @@ -1505,7 +1519,7 @@ static void __kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)

level_pending = vgic_process_maintenance(vcpu);
elrsr = vgic_get_elrsr(vcpu);
elrsr_ptr = (unsigned long *)&elrsr;
elrsr_ptr = u64_to_bitmask(&elrsr);

/* Clear mappings for empty LRs */
for_each_set_bit(lr, elrsr_ptr, vgic->nr_lr) {
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