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From:   Marc Zyngier <maz@kernel.org>
To:     Quentin Perret <qperret@google.com>
Cc:     catalin.marinas@arm.com, james.morse@arm.com,
        julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com,
        android-kvm@google.com, seanjc@google.com, mate.toth-pal@arm.com,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        kernel-team@android.com, kvmarm@lists.cs.columbia.edu,
        tabba@google.com, ardb@kernel.org, mark.rutland@arm.com,
        dbrazdil@google.com
Subject: [PATCH v2 3/3] KVM: arm64: Drop the CPU_FTR_REG_HYP_COPY infrastructure
Date:   Mon, 22 Mar 2021 17:56:39 +0000
Message-Id: <20210322175639.801566-4-maz@kernel.org>
In-Reply-To: <20210322175639.801566-1-maz@kernel.org>
References: <20210322175639.801566-1-maz@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Now that the read_ctr macro has been specialised for nVHE,
the whole CPU_FTR_REG_HYP_COPY infrastrcture looks completely
overengineered.

Simplify it by populating the two u64 quantities (MMFR0 and 1)
that the hypervisor need.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/cpufeature.h     |  1 -
 arch/arm64/include/asm/kvm_cpufeature.h | 26 -------------------------
 arch/arm64/include/asm/kvm_host.h       |  4 ----
 arch/arm64/include/asm/kvm_hyp.h        |  3 +++
 arch/arm64/kernel/cpufeature.c          | 13 -------------
 arch/arm64/kvm/arm.c                    |  3 +++
 arch/arm64/kvm/hyp/nvhe/hyp-smp.c       |  8 --------
 arch/arm64/kvm/hyp/nvhe/mem_protect.c   | 16 ++++++++-------
 arch/arm64/kvm/sys_regs.c               | 22 ---------------------
 9 files changed, 15 insertions(+), 81 deletions(-)
 delete mode 100644 arch/arm64/include/asm/kvm_cpufeature.h

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index a85cea2cac57..61177bac49fa 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -607,7 +607,6 @@ void check_local_cpu_capabilities(void);
 
 u64 read_sanitised_ftr_reg(u32 id);
 u64 __read_sysreg_by_encoding(u32 sys_id);
-int copy_ftr_reg(u32 id, struct arm64_ftr_reg *dst);
 
 static inline bool cpu_supports_mixed_endian_el0(void)
 {
diff --git a/arch/arm64/include/asm/kvm_cpufeature.h b/arch/arm64/include/asm/kvm_cpufeature.h
deleted file mode 100644
index ff302d15e840..000000000000
--- a/arch/arm64/include/asm/kvm_cpufeature.h
+++ /dev/null
@@ -1,26 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Copyright (C) 2020 - Google LLC
- * Author: Quentin Perret <qperret@google.com>
- */
-
-#ifndef __ARM64_KVM_CPUFEATURE_H__
-#define __ARM64_KVM_CPUFEATURE_H__
-
-#include <asm/cpufeature.h>
-
-#include <linux/build_bug.h>
-
-#if defined(__KVM_NVHE_HYPERVISOR__)
-#define DECLARE_KVM_HYP_CPU_FTR_REG(name) extern struct arm64_ftr_reg name
-#define DEFINE_KVM_HYP_CPU_FTR_REG(name) struct arm64_ftr_reg name
-#else
-#define DECLARE_KVM_HYP_CPU_FTR_REG(name) extern struct arm64_ftr_reg kvm_nvhe_sym(name)
-#define DEFINE_KVM_HYP_CPU_FTR_REG(name) BUILD_BUG()
-#endif
-
-DECLARE_KVM_HYP_CPU_FTR_REG(arm64_ftr_reg_ctrel0);
-DECLARE_KVM_HYP_CPU_FTR_REG(arm64_ftr_reg_id_aa64mmfr0_el1);
-DECLARE_KVM_HYP_CPU_FTR_REG(arm64_ftr_reg_id_aa64mmfr1_el1);
-
-#endif
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 4859c9de75d7..09979cdec28b 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -740,13 +740,9 @@ void kvm_clr_pmu_events(u32 clr);
 
 void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu);
 void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu);
-
-void setup_kvm_el2_caps(void);
 #else
 static inline void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr) {}
 static inline void kvm_clr_pmu_events(u32 clr) {}
-
-static inline void setup_kvm_el2_caps(void) {}
 #endif
 
 void kvm_vcpu_load_sysregs_vhe(struct kvm_vcpu *vcpu);
diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index de40a565d7e5..8ef9d88826d4 100644
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -116,4 +116,7 @@ int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
 void __noreturn __host_enter(struct kvm_cpu_context *host_ctxt);
 #endif
 
+extern u64 kvm_nvhe_sym(id_aa64mmfr0_el1_sys_val);
+extern u64 kvm_nvhe_sym(id_aa64mmfr1_el1_sys_val);
+
 #endif /* __ARM64_KVM_HYP_H__ */
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 6252476e4e73..066030717a4c 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1154,18 +1154,6 @@ u64 read_sanitised_ftr_reg(u32 id)
 }
 EXPORT_SYMBOL_GPL(read_sanitised_ftr_reg);
 
-int copy_ftr_reg(u32 id, struct arm64_ftr_reg *dst)
-{
-	struct arm64_ftr_reg *regp = get_arm64_ftr_reg(id);
-
-	if (!regp)
-		return -EINVAL;
-
-	*dst = *regp;
-
-	return 0;
-}
-
 #define read_sysreg_case(r)	\
 	case r:		val = read_sysreg_s(r); break;
 
@@ -2785,7 +2773,6 @@ void __init setup_cpu_features(void)
 
 	setup_system_capabilities();
 	setup_elf_hwcaps(arm64_elf_hwcaps);
-	setup_kvm_el2_caps();
 
 	if (system_supports_32bit_el0())
 		setup_elf_hwcaps(compat_elf_hwcaps);
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 368159021dee..2835400fd298 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1730,6 +1730,9 @@ static int kvm_hyp_init_protection(u32 hyp_va_bits)
 	void *addr = phys_to_virt(hyp_mem_base);
 	int ret;
 
+	kvm_nvhe_sym(id_aa64mmfr0_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
+	kvm_nvhe_sym(id_aa64mmfr1_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
+
 	ret = create_hyp_mappings(addr, addr + hyp_mem_size, PAGE_HYP);
 	if (ret)
 		return ret;
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-smp.c b/arch/arm64/kvm/hyp/nvhe/hyp-smp.c
index 17ad1b3a9530..879559057dee 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-smp.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-smp.c
@@ -5,17 +5,9 @@
  */
 
 #include <asm/kvm_asm.h>
-#include <asm/kvm_cpufeature.h>
 #include <asm/kvm_hyp.h>
 #include <asm/kvm_mmu.h>
 
-/*
- * Copies of the host's CPU features registers holding sanitized values.
- */
-DEFINE_KVM_HYP_CPU_FTR_REG(arm64_ftr_reg_ctrel0);
-DEFINE_KVM_HYP_CPU_FTR_REG(arm64_ftr_reg_id_aa64mmfr0_el1);
-DEFINE_KVM_HYP_CPU_FTR_REG(arm64_ftr_reg_id_aa64mmfr1_el1);
-
 /*
  * nVHE copy of data structures tracking available CPU cores.
  * Only entries for CPUs that were online at KVM init are populated.
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 808e2471091b..f4f364aa3282 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -5,7 +5,6 @@
  */
 
 #include <linux/kvm_host.h>
-#include <asm/kvm_cpufeature.h>
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>
 #include <asm/kvm_mmu.h>
@@ -27,6 +26,12 @@ struct host_kvm host_kvm;
 struct hyp_pool host_s2_mem;
 struct hyp_pool host_s2_dev;
 
+/*
+ * Copies of the host's CPU features registers holding sanitized values.
+ */
+u64 id_aa64mmfr0_el1_sys_val;
+u64 id_aa64mmfr1_el1_sys_val;
+
 static const u8 pkvm_hyp_id = 1;
 
 static void *host_s2_zalloc_pages_exact(size_t size)
@@ -72,16 +77,13 @@ static int prepare_s2_pools(void *mem_pgt_pool, void *dev_pgt_pool)
 static void prepare_host_vtcr(void)
 {
 	u32 parange, phys_shift;
-	u64 mmfr0, mmfr1;
-
-	mmfr0 = arm64_ftr_reg_id_aa64mmfr0_el1.sys_val;
-	mmfr1 = arm64_ftr_reg_id_aa64mmfr1_el1.sys_val;
 
 	/* The host stage 2 is id-mapped, so use parange for T0SZ */
-	parange = kvm_get_parange(mmfr0);
+	parange = kvm_get_parange(id_aa64mmfr0_el1_sys_val);
 	phys_shift = id_aa64mmfr0_parange_to_phys_shift(parange);
 
-	host_kvm.arch.vtcr = kvm_get_vtcr(mmfr0, mmfr1, phys_shift);
+	host_kvm.arch.vtcr = kvm_get_vtcr(id_aa64mmfr0_el1_sys_val,
+					  id_aa64mmfr1_el1_sys_val, phys_shift);
 }
 
 int kvm_host_prepare_stage2(void *mem_pgt_pool, void *dev_pgt_pool)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index dfb3b4f9ca84..4f2f1e3145de 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -21,7 +21,6 @@
 #include <asm/debug-monitors.h>
 #include <asm/esr.h>
 #include <asm/kvm_arm.h>
-#include <asm/kvm_cpufeature.h>
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>
 #include <asm/kvm_mmu.h>
@@ -2776,24 +2775,3 @@ void kvm_sys_reg_table_init(void)
 	/* Clear all higher bits. */
 	cache_levels &= (1 << (i*3))-1;
 }
-
-#define CPU_FTR_REG_HYP_COPY(id, name) \
-	{ .sys_id = id, .dst = (struct arm64_ftr_reg *)&kvm_nvhe_sym(name) }
-struct __ftr_reg_copy_entry {
-	u32			sys_id;
-	struct arm64_ftr_reg	*dst;
-} hyp_ftr_regs[] __initdata = {
-	CPU_FTR_REG_HYP_COPY(SYS_CTR_EL0, arm64_ftr_reg_ctrel0),
-	CPU_FTR_REG_HYP_COPY(SYS_ID_AA64MMFR0_EL1, arm64_ftr_reg_id_aa64mmfr0_el1),
-	CPU_FTR_REG_HYP_COPY(SYS_ID_AA64MMFR1_EL1, arm64_ftr_reg_id_aa64mmfr1_el1),
-};
-
-void __init setup_kvm_el2_caps(void)
-{
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(hyp_ftr_regs); i++) {
-		WARN(copy_ftr_reg(hyp_ftr_regs[i].sys_id, hyp_ftr_regs[i].dst),
-		     "%u feature register not found\n", hyp_ftr_regs[i].sys_id);
-	}
-}
-- 
2.29.2