[PATCH v2 35/94] KVM: arm64: Check advertised Stage-2 page size capability
From: Marc Zyngier <maz@kernel.org>
Date: 2020-02-11 18:12:45
Also in:
kvm, kvmarm
Subsystem:
arm port, arm64 port (aarch64 architecture), kernel virtual machine (kvm), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Russell King, Catalin Marinas, Will Deacon, Paolo Bonzini, Marc Zyngier, Oliver Upton, Linus Torvalds
With ARMv8.5-GTG, the hardware (or more likely a hypervisor) can advertise the supported Stage-2 page sizes. Let's check this at boot time. Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm/include/asm/kvm_mmu.h | 2 +- arch/arm64/include/asm/kvm_host.h | 2 +- arch/arm64/kernel/cpufeature.c | 8 +++++++ arch/arm64/kvm/reset.c | 39 ++++++++++++++++++++++++++++--- virt/kvm/arm/arm.c | 4 +--- 5 files changed, 47 insertions(+), 8 deletions(-)
diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h
index 0d84d50bf9ba..053a5f434b3e 100644
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h@@ -418,7 +418,7 @@ static inline int hyp_map_aux_data(void) #define kvm_phys_to_vttbr(addr) (addr) -static inline void kvm_set_ipa_limit(void) {} +static inline int kvm_set_ipa_limit(void) { return 0; } static __always_inline u64 kvm_get_vttbr(struct kvm *kvm) {
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 1bda11cc0f39..87ccceb9f5d8 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h@@ -734,7 +734,7 @@ static inline int kvm_arm_have_ssbd(void) void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu); void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu); -void kvm_set_ipa_limit(void); +int kvm_set_ipa_limit(void); #define __KVM_HAVE_ARCH_VM_ALLOC struct kvm *kvm_arch_alloc_vm(void);
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index f0e58450eb16..157700590aa8 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c@@ -205,6 +205,14 @@ static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = { }; static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = { + /* + * Page size not being supported at Stage-2 are not fatal. You + * just give up KVM if PAGE_SIZE isn't supported there. Go fix + * your favourite nesting hypervisor. + */ + ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64MMFR0_TGRAN4_2_SHIFT, 4, 1), + ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64MMFR0_TGRAN64_2_SHIFT, 4, 1), + ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64MMFR0_TGRAN16_2_SHIFT, 4, 1), /* * We already refuse to boot CPUs that don't support our configured * page size, so we can only detect mismatches for a page size other
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 5c50df274239..038765d1e60d 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c@@ -348,11 +348,42 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu) return ret; } -void kvm_set_ipa_limit(void) +int kvm_set_ipa_limit(void) { - unsigned int ipa_max, pa_max, va_max, parange; + unsigned int ipa_max, pa_max, va_max, parange, tgran_2; + u64 mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1); - parange = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1) & 0x7; + /* + * Check with ARMv8.5-GTG that our PAGE_SIZE is supported at + * Stage-2. If not, things will stop very quickly. + */ + switch (PAGE_SIZE) { + default: + case SZ_4K: + tgran_2 = ID_AA64MMFR0_TGRAN4_2_SHIFT; + break; + case SZ_16K: + tgran_2 = ID_AA64MMFR0_TGRAN16_2_SHIFT; + break; + case SZ_64K: + tgran_2 = ID_AA64MMFR0_TGRAN64_2_SHIFT; + break; + } + + switch (FIELD_GET(0xFUL << tgran_2, mmfr0)) { + default: + case 1: + kvm_err("PAGE_SIZE not supported at Stage-2, giving up\n"); + return -EINVAL; + case 0: + kvm_debug("PAGE_SIZE supported at Stage-2 (default)\n"); + break; + case 2: + kvm_debug("PAGE_SIZE supported at Stage-2 (advertised)\n"); + break; + } + + parange = mmfr0 & 0x7; pa_max = id_aa64mmfr0_parange_to_phys_shift(parange); /* Clamp the IPA limit to the PA size supported by the kernel */
@@ -386,6 +417,8 @@ void kvm_set_ipa_limit(void) "KVM IPA limit (%d bit) is smaller than default size\n", ipa_max); kvm_ipa_limit = ipa_max; kvm_info("IPA Size Limit: %dbits\n", kvm_ipa_limit); + + return 0; } /*
diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index d65a0faa46d8..d1359b2079df 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c@@ -1421,9 +1421,7 @@ static inline void hyp_cpu_pm_exit(void) static int init_common_resources(void) { - kvm_set_ipa_limit(); - - return 0; + return kvm_set_ipa_limit(); } static int init_subsystems(void)
--
2.20.1
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