From: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
To: <linux-arm-kernel@lists.infradead.org>,
<kvmarm@lists.cs.columbia.edu>, <linux-kernel@vger.kernel.org>
Cc: <maz@kernel.org>, <will@kernel.org>, <catalin.marinas@arm.com>,
<james.morse@arm.com>, <julien.thierry.kdev@gmail.com>,
<suzuki.poulose@arm.com>, <jean-philippe@linaro.org>,
<julien@xen.org>, <linuxarm@huawei.com>
Subject: [PATCH v4 15/16] arch/arm64: Introduce a capability to tell whether 16-bit VMID is available
Date: Wed, 14 Apr 2021 12:23:11 +0100 [thread overview]
Message-ID: <20210414112312.13704-16-shameerali.kolothum.thodi@huawei.com> (raw)
In-Reply-To: <20210414112312.13704-1-shameerali.kolothum.thodi@huawei.com>
From: Julien Grall <julien.grall@arm.com>
At the moment, the function kvm_get_vmid_bits() is looking up for the
sanitized value of ID_AA64MMFR1_EL1 and extract the information
regarding the number of VMID bits supported.
This is fine as the function is mainly used during VMID roll-over. New
use in a follow-up patch will require the function to be called a every
context switch so we want the function to be more efficient.
A new capability is introduced to tell whether 16-bit VMID is
available.
Signed-off-by: Julien Grall <julien.grall@arm.com>
---
arch/arm64/include/asm/cpucaps.h | 3 ++-
arch/arm64/include/asm/kvm_mmu.h | 4 +---
arch/arm64/kernel/cpufeature.c | 9 +++++++++
3 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index c40f2490cd7b..acb92da5c254 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -67,7 +67,8 @@
#define ARM64_HAS_LDAPR 59
#define ARM64_KVM_PROTECTED_MODE 60
#define ARM64_WORKAROUND_NVIDIA_CARMEL_CNP 61
+#define ARM64_HAS_16BIT_VMID 62
-#define ARM64_NCAPS 62
+#define ARM64_NCAPS 63
#endif /* __ASM_CPUCAPS_H */
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 90873851f677..c3080966ef83 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -213,9 +213,7 @@ void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled);
static inline unsigned int kvm_get_vmid_bits(void)
{
- int reg = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
-
- return get_vmid_bits(reg);
+ return cpus_have_const_cap(ARM64_HAS_16BIT_VMID) ? 16 : 8;
}
/*
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index e5281e1c8f1d..ff956fb2f712 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -2203,6 +2203,15 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.matches = has_cpuid_feature,
.min_field_value = 1,
},
+ {
+ .capability = ARM64_HAS_16BIT_VMID,
+ .type = ARM64_CPUCAP_SYSTEM_FEATURE,
+ .sys_reg = SYS_ID_AA64MMFR1_EL1,
+ .field_pos = ID_AA64MMFR1_VMIDBITS_SHIFT,
+ .sign = FTR_UNSIGNED,
+ .min_field_value = ID_AA64MMFR1_VMIDBITS_16,
+ .matches = has_cpuid_feature,
+ },
{},
};
--
2.17.1
next prev parent reply other threads:[~2021-04-14 11:26 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-14 11:22 [PATCH v4 00/16] kvm/arm: Align the VMID allocation with the arm64 ASID one Shameer Kolothum
2021-04-14 11:22 ` [PATCH v4 01/16] arm64/mm: Introduce asid_info structure and move asid_generation/asid_map to it Shameer Kolothum
2021-04-14 11:22 ` [PATCH v4 02/16] arm64/mm: Move active_asids and reserved_asids to asid_info Shameer Kolothum
2021-04-14 11:22 ` [PATCH v4 03/16] arm64/mm: Move bits " Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 04/16] arm64/mm: Move the variable lock and tlb_flush_pending " Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 05/16] arm64/mm: Remove dependency on MM in new_context Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 06/16] arm64/mm: Introduce NUM_CTXT_ASIDS Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 07/16] arm64/mm: Move Pinned ASID related variables to asid_info Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 08/16] arm64/mm: Split asid_inits in 2 parts Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 09/16] arm64/mm: Split the function check_and_switch_context in 3 parts Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 10/16] arm64/mm: Split the arm64_mm_context_get/put Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 11/16] arm64/mm: Introduce a callback to flush the local context Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 12/16] arm64/mm: Introduce a callback to set reserved bits Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 13/16] arm64: Move the ASID allocator code in a separate file Shameer Kolothum
2021-04-14 11:23 ` [PATCH v4 14/16] arm64/lib: Add an helper to free memory allocated by the ASID allocator Shameer Kolothum
2021-04-14 11:23 ` Shameer Kolothum [this message]
2021-04-14 11:23 ` [PATCH v4 16/16] kvm/arm: Align the VMID allocation with the arm64 ASID one Shameer Kolothum
2021-04-22 16:08 ` [PATCH v4 00/16] " Will Deacon
2021-04-23 8:31 ` Shameerali Kolothum Thodi
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