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authorMarc Zyngier <marc.zyngier@arm.com>2016-04-05 16:11:47 +0100
committerChristoffer Dall <christoffer.dall@linaro.org>2016-04-06 13:33:14 +0200
commit6141570c36f0c937d5deff20d9cf08cbd8d8ed48 (patch)
tree321db1eba7dba333aed3b4f22305c02227ff3038 /arch/arm64
parent1c5631c73fc2261a5df64a72c155cb53dcdc0c45 (diff)
downloadlinux-6141570c36f0c937d5deff20d9cf08cbd8d8ed48.tar.gz
arm64: KVM: Warn when PARange is less than 40 bits
We always thought that 40bits of PA range would be the minimum people would actually build. Anything less is terrifyingly small. Turns out that we were both right and wrong. Nobody has ever built such a system, but the ARM Foundation Model has a PARange set to 36bits. Just because we can. Oh well. Now, the KVM API explicitely says that we offer a 40bit PA space to the VM, so we shouldn't run KVM on the Foundation Model at all. That being said, this patch offers a less agressive alternative, and loudly warns about the configuration being unsupported. You'll still be able to run VMs (at your own risks, though). This is just a workaround until we have a proper userspace API where we report the PARange to userspace. Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'arch/arm64')
-rw-r--r--arch/arm64/include/asm/kvm_arm.h6
-rw-r--r--arch/arm64/include/asm/kvm_asm.h2
-rw-r--r--arch/arm64/include/asm/kvm_host.h7
-rw-r--r--arch/arm64/kvm/hyp/s2-setup.c39
4 files changed, 44 insertions, 10 deletions
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index 4150fd8bae01..3f29887995bc 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -151,8 +151,7 @@
*/
#define VTCR_EL2_FLAGS (VTCR_EL2_TG0_64K | VTCR_EL2_SH0_INNER | \
VTCR_EL2_ORGN0_WBWA | VTCR_EL2_IRGN0_WBWA | \
- VTCR_EL2_SL0_LVL1 | VTCR_EL2_T0SZ_40B | \
- VTCR_EL2_RES1)
+ VTCR_EL2_SL0_LVL1 | VTCR_EL2_RES1)
#define VTTBR_X (38 - VTCR_EL2_T0SZ_40B)
#else
/*
@@ -163,8 +162,7 @@
*/
#define VTCR_EL2_FLAGS (VTCR_EL2_TG0_4K | VTCR_EL2_SH0_INNER | \
VTCR_EL2_ORGN0_WBWA | VTCR_EL2_IRGN0_WBWA | \
- VTCR_EL2_SL0_LVL1 | VTCR_EL2_T0SZ_40B | \
- VTCR_EL2_RES1)
+ VTCR_EL2_SL0_LVL1 | VTCR_EL2_RES1)
#define VTTBR_X (37 - VTCR_EL2_T0SZ_40B)
#endif
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index eb7490d232a0..40a0a24e6c98 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -54,7 +54,7 @@ extern void __vgic_v3_init_lrs(void);
extern u32 __kvm_get_mdcr_el2(void);
-extern void __init_stage2_translation(void);
+extern u32 __init_stage2_translation(void);
#endif
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 227ed475dbd3..4cd4196e94a9 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -370,11 +370,12 @@ int kvm_arm_vcpu_arch_get_attr(struct kvm_vcpu *vcpu,
int kvm_arm_vcpu_arch_has_attr(struct kvm_vcpu *vcpu,
struct kvm_device_attr *attr);
-/* #define kvm_call_hyp(f, ...) __kvm_call_hyp(kvm_ksym_ref(f), ##__VA_ARGS__) */
-
static inline void __cpu_init_stage2(void)
{
- kvm_call_hyp(__init_stage2_translation);
+ u32 parange = kvm_call_hyp(__init_stage2_translation);
+
+ WARN_ONCE(parange < 40,
+ "PARange is %d bits, unsupported configuration!", parange);
}
#endif /* __ARM64_KVM_HOST_H__ */
diff --git a/arch/arm64/kvm/hyp/s2-setup.c b/arch/arm64/kvm/hyp/s2-setup.c
index 5a9f3bf542b0..bcbe761a5a3d 100644
--- a/arch/arm64/kvm/hyp/s2-setup.c
+++ b/arch/arm64/kvm/hyp/s2-setup.c
@@ -20,9 +20,10 @@
#include <asm/kvm_asm.h>
#include <asm/kvm_hyp.h>
-void __hyp_text __init_stage2_translation(void)
+u32 __hyp_text __init_stage2_translation(void)
{
u64 val = VTCR_EL2_FLAGS;
+ u64 parange;
u64 tmp;
/*
@@ -30,7 +31,39 @@ void __hyp_text __init_stage2_translation(void)
* bits in VTCR_EL2. Amusingly, the PARange is 4 bits, while
* PS is only 3. Fortunately, bit 19 is RES0 in VTCR_EL2...
*/
- val |= (read_sysreg(id_aa64mmfr0_el1) & 7) << 16;
+ parange = read_sysreg(id_aa64mmfr0_el1) & 7;
+ val |= parange << 16;
+
+ /* Compute the actual PARange... */
+ switch (parange) {
+ case 0:
+ parange = 32;
+ break;
+ case 1:
+ parange = 36;
+ break;
+ case 2:
+ parange = 40;
+ break;
+ case 3:
+ parange = 42;
+ break;
+ case 4:
+ parange = 44;
+ break;
+ case 5:
+ default:
+ parange = 48;
+ break;
+ }
+
+ /*
+ * ... and clamp it to 40 bits, unless we have some braindead
+ * HW that implements less than that. In all cases, we'll
+ * return that value for the rest of the kernel to decide what
+ * to do.
+ */
+ val |= 64 - (parange > 40 ? 40 : parange);
/*
* Read the VMIDBits bits from ID_AA64MMFR1_EL1 and set the VS
@@ -42,4 +75,6 @@ void __hyp_text __init_stage2_translation(void)
VTCR_EL2_VS_8BIT;
write_sysreg(val, vtcr_el2);
+
+ return parange;
}