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authorMarc Zyngier <marc.zyngier@arm.com>2014-12-19 16:05:31 +0000
committerChristoffer Dall <christoffer.dall@linaro.org>2015-01-29 23:24:56 +0100
commit3c1e716508335eb132c9349cb1a1716c8f7e3d2e (patch)
tree39aa2fe691caa61a34cef1ac7d09f3348249ddb5 /arch/arm64/kvm
parentf3747379accba8e95d70cec0eae0582c8c182050 (diff)
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arm/arm64: KVM: Use set/way op trapping to track the state of the caches
Trying to emulate the behaviour of set/way cache ops is fairly pointless, as there are too many ways we can end-up missing stuff. Also, there is some system caches out there that simply ignore set/way operations. So instead of trying to implement them, let's convert it to VA ops, and use them as a way to re-enable the trapping of VM ops. That way, we can detect the point when the MMU/caches are turned off, and do a full VM flush (which is what the guest was trying to do anyway). This allows a 32bit zImage to boot on the APM thingy, and will probably help bootloaders in general. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'arch/arm64/kvm')
-rw-r--r--arch/arm64/kvm/sys_regs.c75
1 files changed, 10 insertions, 65 deletions
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 3d7c2df89946..f31e8bb2bc5b 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -69,68 +69,31 @@ static u32 get_ccsidr(u32 csselr)
return ccsidr;
}
-static void do_dc_cisw(u32 val)
-{
- asm volatile("dc cisw, %x0" : : "r" (val));
- dsb(ish);
-}
-
-static void do_dc_csw(u32 val)
-{
- asm volatile("dc csw, %x0" : : "r" (val));
- dsb(ish);
-}
-
-/* See note at ARM ARM B1.14.4 */
+/*
+ * See note at ARMv7 ARM B1.14.4 (TL;DR: S/W ops are not easily virtualized).
+ */
static bool access_dcsw(struct kvm_vcpu *vcpu,
const struct sys_reg_params *p,
const struct sys_reg_desc *r)
{
- unsigned long val;
- int cpu;
-
if (!p->is_write)
return read_from_write_only(vcpu, p);
- cpu = get_cpu();
-
- cpumask_setall(&vcpu->arch.require_dcache_flush);
- cpumask_clear_cpu(cpu, &vcpu->arch.require_dcache_flush);
-
- /* If we were already preempted, take the long way around */
- if (cpu != vcpu->arch.last_pcpu) {
- flush_cache_all();
- goto done;
- }
-
- val = *vcpu_reg(vcpu, p->Rt);
-
- switch (p->CRm) {
- case 6: /* Upgrade DCISW to DCCISW, as per HCR.SWIO */
- case 14: /* DCCISW */
- do_dc_cisw(val);
- break;
-
- case 10: /* DCCSW */
- do_dc_csw(val);
- break;
- }
-
-done:
- put_cpu();
-
+ kvm_set_way_flush(vcpu);
return true;
}
/*
* Generic accessor for VM registers. Only called as long as HCR_TVM
- * is set.
+ * is set. If the guest enables the MMU, we stop trapping the VM
+ * sys_regs and leave it in complete control of the caches.
*/
static bool access_vm_reg(struct kvm_vcpu *vcpu,
const struct sys_reg_params *p,
const struct sys_reg_desc *r)
{
unsigned long val;
+ bool was_enabled = vcpu_has_cache_enabled(vcpu);
BUG_ON(!p->is_write);
@@ -143,25 +106,7 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu,
vcpu_cp15_64_low(vcpu, r->reg) = val & 0xffffffffUL;
}
- return true;
-}
-
-/*
- * SCTLR_EL1 accessor. Only called as long as HCR_TVM is set. If the
- * guest enables the MMU, we stop trapping the VM sys_regs and leave
- * it in complete control of the caches.
- */
-static bool access_sctlr(struct kvm_vcpu *vcpu,
- const struct sys_reg_params *p,
- const struct sys_reg_desc *r)
-{
- access_vm_reg(vcpu, p, r);
-
- if (vcpu_has_cache_enabled(vcpu)) { /* MMU+Caches enabled? */
- vcpu->arch.hcr_el2 &= ~HCR_TVM;
- stage2_flush_vm(vcpu->kvm);
- }
-
+ kvm_toggle_cache(vcpu, was_enabled);
return true;
}
@@ -377,7 +322,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
NULL, reset_mpidr, MPIDR_EL1 },
/* SCTLR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b000),
- access_sctlr, reset_val, SCTLR_EL1, 0x00C50078 },
+ access_vm_reg, reset_val, SCTLR_EL1, 0x00C50078 },
/* CPACR_EL1 */
{ Op0(0b11), Op1(0b000), CRn(0b0001), CRm(0b0000), Op2(0b010),
NULL, reset_val, CPACR_EL1, 0 },
@@ -657,7 +602,7 @@ static const struct sys_reg_desc cp14_64_regs[] = {
* register).
*/
static const struct sys_reg_desc cp15_regs[] = {
- { Op1( 0), CRn( 1), CRm( 0), Op2( 0), access_sctlr, NULL, c1_SCTLR },
+ { Op1( 0), CRn( 1), CRm( 0), Op2( 0), access_vm_reg, NULL, c1_SCTLR },
{ Op1( 0), CRn( 2), CRm( 0), Op2( 0), access_vm_reg, NULL, c2_TTBR0 },
{ Op1( 0), CRn( 2), CRm( 0), Op2( 1), access_vm_reg, NULL, c2_TTBR1 },
{ Op1( 0), CRn( 2), CRm( 0), Op2( 2), access_vm_reg, NULL, c2_TTBCR },
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