From 7f19cf521f49f3df6801cb2acf421215c2a35cb2 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Thu, 25 Nov 2021 14:14:44 +0000 Subject: [PATCH] ANDROID: KVM: arm64: Allow userspace to receive SHARE and UNSHARE notifications Expose MEM_SHARE and MEM_UNSHARE hypercalls to the KVM_CAP_EXIT_HYPERCALL capability, allowing userspace (i.e. the VMM) to mprotect() its own mapping of the pages based upon changes to the host permissions. Signed-off-by: Will Deacon Bug: 209580772 Change-Id: I95890595f8cc5493a5a67636bd22da3cc90a95fc Signed-off-by: Will Deacon --- arch/arm64/kvm/arm.c | 3 ++- arch/arm64/kvm/hypercalls.c | 8 ++++++++ 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 0246e05fde9a..542f05684f4a 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -64,7 +64,8 @@ static DEFINE_PER_CPU(unsigned char, kvm_arm_hardware_enabled); DEFINE_STATIC_KEY_FALSE(userspace_irqchip_in_use); /* KVM "vendor" hypercalls which may be forwarded to userspace on request. */ -#define KVM_EXIT_HYPERCALL_VALID_MASK (0) +#define KVM_EXIT_HYPERCALL_VALID_MASK (BIT(ARM_SMCCC_KVM_FUNC_MEM_SHARE) | \ + BIT(ARM_SMCCC_KVM_FUNC_MEM_UNSHARE)) int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu) { diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c index e41571fa90aa..96be98381719 100644 --- a/arch/arm64/kvm/hypercalls.c +++ b/arch/arm64/kvm/hypercalls.c @@ -151,6 +151,14 @@ int kvm_hvc_call_handler(struct kvm_vcpu *vcpu) case ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID: kvm_ptp_get_time(vcpu, val); break; + case ARM_SMCCC_VENDOR_HYP_KVM_MEM_SHARE_FUNC_ID: + if (!kvm_vcpu_exit_hcall(vcpu, ARM_SMCCC_KVM_FUNC_MEM_SHARE, 3)) + return 0; + break; + case ARM_SMCCC_VENDOR_HYP_KVM_MEM_UNSHARE_FUNC_ID: + if (!kvm_vcpu_exit_hcall(vcpu, ARM_SMCCC_KVM_FUNC_MEM_UNSHARE, 3)) + return 0; + break; case ARM_SMCCC_TRNG_VERSION: case ARM_SMCCC_TRNG_FEATURES: case ARM_SMCCC_TRNG_GET_UUID: