From 5368f83fc956e30647118046c6b0f29522fa8537 Mon Sep 17 00:00:00 2001
From: Vladimir Murzin <vladimir.murzin@arm.com>
Date: Tue, 31 Jul 2018 14:08:57 +0100
Subject: [PATCH] arm64: KVM: Enable Common Not Private translations
Git-commit: ab510027dc4dbd1eeb611a34b0cda8b21fcde492
Patch-mainline: v4.20-rc1
References: fate#325862
We rely on cpufeature framework to detect and enable CNP so for KVM we
need to patch hyp to set CNP bit just before TTBR0_EL2 gets written.
For the guest we encode CNP bit while building vttbr, so we don't need
to bother with that in a world switch.
Reviewed-by: James Morse <james.morse@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
arch/arm/include/asm/kvm_arm.h | 1 +
arch/arm/include/asm/kvm_mmu.h | 5 +++++
arch/arm64/include/asm/kvm_arm.h | 1 +
arch/arm64/include/asm/kvm_mmu.h | 5 +++++
arch/arm64/kvm/hyp-init.S | 3 +++
virt/kvm/arm/arm.c | 4 ++--
6 files changed, 17 insertions(+), 2 deletions(-)
--- a/arch/arm/include/asm/kvm_arm.h
+++ b/arch/arm/include/asm/kvm_arm.h
@@ -161,6 +161,7 @@
#else
#define VTTBR_X (5 - KVM_T0SZ)
#endif
+#define VTTBR_CNP_BIT _AC(1, UL)
#define VTTBR_BADDR_MASK (((_AC(1, ULL) << (40 - VTTBR_X)) - 1) << VTTBR_X)
#define VTTBR_VMID_SHIFT _AC(48, ULL)
#define VTTBR_VMID_MASK(size) (_AT(u64, (1 << size) - 1) << VTTBR_VMID_SHIFT)
--- a/arch/arm/include/asm/kvm_mmu.h
+++ b/arch/arm/include/asm/kvm_mmu.h
@@ -228,6 +228,11 @@ static inline unsigned int kvm_get_vmid_
#define kvm_phys_to_vttbr(addr) (addr)
+static inline bool kvm_cpu_has_cnp(void)
+{
+ return false;
+}
+
/*
* We are not in the kvm->srcu critical section most of the time, so we take
* the SRCU read lock here. Since we copy the data from the user page, we
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -172,6 +172,7 @@
#define VTCR_EL2_FLAGS (VTCR_EL2_COMMON_BITS | VTCR_EL2_TGRAN_FLAGS)
#define VTTBR_X (VTTBR_X_TGRAN_MAGIC - VTCR_EL2_T0SZ_IPA)
+#define VTTBR_CNP_BIT (UL(1))
#define VTTBR_BADDR_MASK (((UL(1) << (PHYS_MASK_SHIFT - VTTBR_X)) - 1) << VTTBR_X)
#define VTTBR_VMID_SHIFT (UL(48))
#define VTTBR_VMID_MASK(size) (_AT(u64, (1 << size) - 1) << VTTBR_VMID_SHIFT)
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -324,6 +324,11 @@ static inline unsigned int kvm_get_vmid_
#define kvm_phys_to_vttbr(addr) phys_to_ttbr(addr)
+static inline bool kvm_cpu_has_cnp(void)
+{
+ return system_supports_cnp();
+}
+
/*
* We are not in the kvm->srcu critical section most of the time, so we take
* the SRCU read lock here. Since we copy the data from the user page, we
--- a/arch/arm64/kvm/hyp-init.S
+++ b/arch/arm64/kvm/hyp-init.S
@@ -64,6 +64,9 @@ __do_hyp_init:
b.lo __kvm_handle_stub_hvc
phys_to_ttbr x4, x0
+alternative_if ARM64_HAS_CNP
+ orr x4, x4, #TTBR_CNP_BIT
+alternative_else_nop_endif
msr ttbr0_el2, x4
mrs x4, tcr_el1
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -479,7 +479,7 @@ static bool need_new_vmid_gen(struct kvm
static void update_vttbr(struct kvm *kvm)
{
phys_addr_t pgd_phys;
- u64 vmid;
+ u64 vmid, cnp = kvm_cpu_has_cnp() ? VTTBR_CNP_BIT : 0;
bool new_gen;
read_lock(&kvm_vmid_lock);
@@ -529,7 +529,7 @@ static void update_vttbr(struct kvm *kvm
pgd_phys = virt_to_phys(kvm->arch.pgd);
BUG_ON(pgd_phys & ~VTTBR_BADDR_MASK);
vmid = ((u64)(kvm->arch.vmid) << VTTBR_VMID_SHIFT) & VTTBR_VMID_MASK(kvm_vmid_bits);
- kvm->arch.vttbr = kvm_phys_to_vttbr(pgd_phys) | vmid;
+ kvm->arch.vttbr = kvm_phys_to_vttbr(pgd_phys) | vmid | cnp;
write_unlock(&kvm_vmid_lock);
}