[PATCH v4 15/23] arm64: KVM: VHE: Implement VHE activate/deactivate_traps
From: Marc Zyngier <hidden>
Date: 2016-02-11 18:40:37
Also in:
kvm, kvmarm, lkml
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
Running the kernel in HYP mode requires the HCR_E2H bit to be set at all times, and the HCR_TGE bit to be set when running as a host (and cleared when running as a guest). At the same time, the vector must be set to the current role of the kernel (either host or hypervisor), and a couple of system registers differ between VHE and non-VHE. We implement these by using another set of alternate functions that get dynamically patched. Reviewed-by: Christoffer Dall <redacted> Signed-off-by: Marc Zyngier <redacted> --- arch/arm64/include/asm/kvm_arm.h | 3 +- arch/arm64/include/asm/kvm_emulate.h | 3 ++ arch/arm64/kvm/hyp/switch.c | 53 ++++++++++++++++++++++++++++++++---- 3 files changed, 52 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index f416714..95ee31e 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h@@ -23,6 +23,7 @@ #include <asm/types.h> /* Hyp Configuration Register (HCR) bits */ +#define HCR_E2H (UL(1) << 34) #define HCR_ID (UL(1) << 33) #define HCR_CD (UL(1) << 32) #define HCR_RW_SHIFT 31
@@ -81,7 +82,7 @@ HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW) #define HCR_VIRT_EXCP_MASK (HCR_VA | HCR_VI | HCR_VF) #define HCR_INT_OVERRIDE (HCR_FMO | HCR_IMO) - +#define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H) /* Hyp System Control Register (SCTLR_EL2) bits */ #define SCTLR_EL2_EE (1 << 25)
diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 779a587..ae7cdac 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h@@ -29,6 +29,7 @@ #include <asm/kvm_mmio.h> #include <asm/ptrace.h> #include <asm/cputype.h> +#include <asm/virt.h> unsigned long *vcpu_reg32(const struct kvm_vcpu *vcpu, u8 reg_num); unsigned long *vcpu_spsr32(const struct kvm_vcpu *vcpu);
@@ -43,6 +44,8 @@ void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr); static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu) { vcpu->arch.hcr_el2 = HCR_GUEST_FLAGS; + if (is_kernel_in_hyp_mode()) + vcpu->arch.hcr_el2 |= HCR_E2H; if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) vcpu->arch.hcr_el2 &= ~HCR_RW; }
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 0d82ae9..e609942 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c@@ -15,6 +15,8 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ +#include <asm/kvm_asm.h> + #include "hyp.h" static bool __hyp_text __fpsimd_enabled_nvhe(void)
@@ -36,6 +38,31 @@ bool __hyp_text __fpsimd_enabled(void) return __fpsimd_is_enabled()(); } +static void __hyp_text __activate_traps_vhe(void) +{ + u64 val; + + val = read_sysreg(cpacr_el1); + val |= CPACR_EL1_TTA; + val &= ~CPACR_EL1_FPEN; + write_sysreg(val, cpacr_el1); + + write_sysreg(__kvm_hyp_vector, vbar_el1); +} + +static void __hyp_text __activate_traps_nvhe(void) +{ + u64 val; + + val = CPTR_EL2_DEFAULT; + val |= CPTR_EL2_TTA | CPTR_EL2_TFP; + write_sysreg(val, cptr_el2); +} + +static hyp_alternate_select(__activate_traps_arch, + __activate_traps_nvhe, __activate_traps_vhe, + ARM64_HAS_VIRT_HOST_EXTN); + static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu) { u64 val;
@@ -55,20 +82,34 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu) write_sysreg(val, hcr_el2); /* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */ write_sysreg(1 << 15, hstr_el2); + write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2); + __activate_traps_arch()(); +} - val = CPTR_EL2_DEFAULT; - val |= CPTR_EL2_TTA | CPTR_EL2_TFP; - write_sysreg(val, cptr_el2); +static void __hyp_text __deactivate_traps_vhe(void) +{ + extern char vectors[]; /* kernel exception vectors */ - write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2); + write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2); + write_sysreg(CPACR_EL1_FPEN, cpacr_el1); + write_sysreg(vectors, vbar_el1); } -static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu) +static void __hyp_text __deactivate_traps_nvhe(void) { write_sysreg(HCR_RW, hcr_el2); + write_sysreg(CPTR_EL2_DEFAULT, cptr_el2); +} + +static hyp_alternate_select(__deactivate_traps_arch, + __deactivate_traps_nvhe, __deactivate_traps_vhe, + ARM64_HAS_VIRT_HOST_EXTN); + +static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu) +{ + __deactivate_traps_arch()(); write_sysreg(0, hstr_el2); write_sysreg(read_sysreg(mdcr_el2) & MDCR_EL2_HPMN_MASK, mdcr_el2); - write_sysreg(CPTR_EL2_DEFAULT, cptr_el2); } static void __hyp_text __activate_vm(struct kvm_vcpu *vcpu)
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2.1.4