From 68925176296a8b995e503349200e256674bfe5ac Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 17 Feb 2017 14:32:18 +0000 Subject: arm64: KVM: VHE: Clear HCR_TGE when invalidating guest TLBs When invalidating guest TLBs, special care must be taken to actually shoot the guest TLBs and not the host ones if we're running on a VHE system. This is controlled by the HCR_EL2.TGE bit, which we forget to clear before invalidating TLBs. Address the issue by introducing two wrappers (__tlb_switch_to_guest and __tlb_switch_to_host) that take care of both the VTTBR_EL2 and HCR_EL2.TGE switching. Reported-by: Tomasz Nowicki Tested-by: Tomasz Nowicki Reviewed-by: Christoffer Dall Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier --- arch/arm64/kvm/hyp/tlb.c | 64 +++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 55 insertions(+), 9 deletions(-) (limited to 'arch') diff --git a/arch/arm64/kvm/hyp/tlb.c b/arch/arm64/kvm/hyp/tlb.c index e8e7ba2bc11f..9e1d2b75eecd 100644 --- a/arch/arm64/kvm/hyp/tlb.c +++ b/arch/arm64/kvm/hyp/tlb.c @@ -18,14 +18,62 @@ #include #include +static void __hyp_text __tlb_switch_to_guest_vhe(struct kvm *kvm) +{ + u64 val; + + /* + * With VHE enabled, we have HCR_EL2.{E2H,TGE} = {1,1}, and + * most TLB operations target EL2/EL0. In order to affect the + * guest TLBs (EL1/EL0), we need to change one of these two + * bits. Changing E2H is impossible (goodbye TTBR1_EL2), so + * let's flip TGE before executing the TLB operation. + */ + write_sysreg(kvm->arch.vttbr, vttbr_el2); + val = read_sysreg(hcr_el2); + val &= ~HCR_TGE; + write_sysreg(val, hcr_el2); + isb(); +} + +static void __hyp_text __tlb_switch_to_guest_nvhe(struct kvm *kvm) +{ + write_sysreg(kvm->arch.vttbr, vttbr_el2); + isb(); +} + +static hyp_alternate_select(__tlb_switch_to_guest, + __tlb_switch_to_guest_nvhe, + __tlb_switch_to_guest_vhe, + ARM64_HAS_VIRT_HOST_EXTN); + +static void __hyp_text __tlb_switch_to_host_vhe(struct kvm *kvm) +{ + /* + * We're done with the TLB operation, let's restore the host's + * view of HCR_EL2. + */ + write_sysreg(0, vttbr_el2); + write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2); +} + +static void __hyp_text __tlb_switch_to_host_nvhe(struct kvm *kvm) +{ + write_sysreg(0, vttbr_el2); +} + +static hyp_alternate_select(__tlb_switch_to_host, + __tlb_switch_to_host_nvhe, + __tlb_switch_to_host_vhe, + ARM64_HAS_VIRT_HOST_EXTN); + void __hyp_text __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa) { dsb(ishst); /* Switch to requested VMID */ kvm = kern_hyp_va(kvm); - write_sysreg(kvm->arch.vttbr, vttbr_el2); - isb(); + __tlb_switch_to_guest()(kvm); /* * We could do so much better if we had the VA as well. @@ -46,7 +94,7 @@ void __hyp_text __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa) dsb(ish); isb(); - write_sysreg(0, vttbr_el2); + __tlb_switch_to_host()(kvm); } void __hyp_text __kvm_tlb_flush_vmid(struct kvm *kvm) @@ -55,14 +103,13 @@ void __hyp_text __kvm_tlb_flush_vmid(struct kvm *kvm) /* Switch to requested VMID */ kvm = kern_hyp_va(kvm); - write_sysreg(kvm->arch.vttbr, vttbr_el2); - isb(); + __tlb_switch_to_guest()(kvm); __tlbi(vmalls12e1is); dsb(ish); isb(); - write_sysreg(0, vttbr_el2); + __tlb_switch_to_host()(kvm); } void __hyp_text __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu) @@ -70,14 +117,13 @@ void __hyp_text __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu) struct kvm *kvm = kern_hyp_va(kern_hyp_va(vcpu)->kvm); /* Switch to requested VMID */ - write_sysreg(kvm->arch.vttbr, vttbr_el2); - isb(); + __tlb_switch_to_guest()(kvm); __tlbi(vmalle1); dsb(nsh); isb(); - write_sysreg(0, vttbr_el2); + __tlb_switch_to_host()(kvm); } void __hyp_text __kvm_flush_vm_context(void) -- cgit v1.2.3 From f050fe7a9164945dd1c28be05bf00e8cfb082ccf Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 20 Feb 2017 12:30:11 +0000 Subject: arm: KVM: Survive unknown traps from guests Currently we BUG() if we see a HSR.EC value we don't recognise. As configurable disables/enables are added to the architecture (controlled by RES1/RES0 bits respectively), with associated synchronous exceptions, it may be possible for a guest to trigger exceptions with classes that we don't recognise. While we can't service these exceptions in a manner useful to the guest, we can avoid bringing down the host. Per ARM DDI 0406C.c, all currently unallocated HSR EC encodings are reserved, and per ARM DDI 0487A.k_iss10775, page G6-4395, EC values within the range 0x00 - 0x2c are reserved for future use with synchronous exceptions, and EC values within the range 0x2d - 0x3f may be used for either synchronous or asynchronous exceptions. The patch makes KVM handle any unknown EC by injecting an UNDEFINED exception into the guest, with a corresponding (ratelimited) warning in the host dmesg. We could later improve on this with with a new (opt-in) exit to the host userspace. Cc: Dave Martin Cc: Suzuki K Poulose Reviewed-by: Christoffer Dall Signed-off-by: Mark Rutland Signed-off-by: Marc Zyngier --- arch/arm/include/asm/kvm_arm.h | 1 + arch/arm/kvm/handle_exit.c | 19 ++++++++++++------- 2 files changed, 13 insertions(+), 7 deletions(-) (limited to 'arch') diff --git a/arch/arm/include/asm/kvm_arm.h b/arch/arm/include/asm/kvm_arm.h index e22089fb44dc..a3f0b3d50089 100644 --- a/arch/arm/include/asm/kvm_arm.h +++ b/arch/arm/include/asm/kvm_arm.h @@ -209,6 +209,7 @@ #define HSR_EC_IABT_HYP (0x21) #define HSR_EC_DABT (0x24) #define HSR_EC_DABT_HYP (0x25) +#define HSR_EC_MAX (0x3f) #define HSR_WFI_IS_WFE (_AC(1, UL) << 0) diff --git a/arch/arm/kvm/handle_exit.c b/arch/arm/kvm/handle_exit.c index 4e40d1955e35..96af65a30d78 100644 --- a/arch/arm/kvm/handle_exit.c +++ b/arch/arm/kvm/handle_exit.c @@ -79,7 +79,19 @@ static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run) return 1; } +static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + u32 hsr = kvm_vcpu_get_hsr(vcpu); + + kvm_pr_unimpl("Unknown exception class: hsr: %#08x\n", + hsr); + + kvm_inject_undefined(vcpu); + return 1; +} + static exit_handle_fn arm_exit_handlers[] = { + [0 ... HSR_EC_MAX] = kvm_handle_unknown_ec, [HSR_EC_WFI] = kvm_handle_wfx, [HSR_EC_CP15_32] = kvm_handle_cp15_32, [HSR_EC_CP15_64] = kvm_handle_cp15_64, @@ -98,13 +110,6 @@ static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu) { u8 hsr_ec = kvm_vcpu_trap_get_class(vcpu); - if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) || - !arm_exit_handlers[hsr_ec]) { - kvm_err("Unknown exception class: hsr: %#08x\n", - (unsigned int)kvm_vcpu_get_hsr(vcpu)); - BUG(); - } - return arm_exit_handlers[hsr_ec]; } -- cgit v1.2.3 From ba4dd156eabdca93501d92a980ba27fa5f4bbd27 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Mon, 20 Feb 2017 12:30:12 +0000 Subject: arm64: KVM: Survive unknown traps from guests Currently we BUG() if we see an ESR_EL2.EC value we don't recognise. As configurable disables/enables are added to the architecture (controlled by RES1/RES0 bits respectively), with associated synchronous exceptions, it may be possible for a guest to trigger exceptions with classes that we don't recognise. While we can't service these exceptions in a manner useful to the guest, we can avoid bringing down the host. Per ARM DDI 0487A.k_iss10775, page D7-1937, EC values within the range 0x00 - 0x2c are reserved for future use with synchronous exceptions, and EC values within the range 0x2d - 0x3f may be used for either synchronous or asynchronous exceptions. The patch makes KVM handle any unknown EC by injecting an UNDEFINED exception into the guest, with a corresponding (ratelimited) warning in the host dmesg. We could later improve on this with with a new (opt-in) exit to the host userspace. Cc: Dave Martin Cc: Suzuki K Poulose Reviewed-by: Christoffer Dall Signed-off-by: Mark Rutland Signed-off-by: Marc Zyngier --- arch/arm64/kvm/handle_exit.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) (limited to 'arch') diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index 1bfe30dfbfe7..fa1b18e364fc 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -135,7 +135,19 @@ static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run) return ret; } +static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + u32 hsr = kvm_vcpu_get_hsr(vcpu); + + kvm_pr_unimpl("Unknown exception class: hsr: %#08x -- %s\n", + hsr, esr_get_class_string(hsr)); + + kvm_inject_undefined(vcpu); + return 1; +} + static exit_handle_fn arm_exit_handlers[] = { + [0 ... ESR_ELx_EC_MAX] = kvm_handle_unknown_ec, [ESR_ELx_EC_WFx] = kvm_handle_wfx, [ESR_ELx_EC_CP15_32] = kvm_handle_cp15_32, [ESR_ELx_EC_CP15_64] = kvm_handle_cp15_64, @@ -162,13 +174,6 @@ static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu) u32 hsr = kvm_vcpu_get_hsr(vcpu); u8 hsr_ec = ESR_ELx_EC(hsr); - if (hsr_ec >= ARRAY_SIZE(arm_exit_handlers) || - !arm_exit_handlers[hsr_ec]) { - kvm_err("Unknown exception class: hsr: %#08x -- %s\n", - hsr, esr_get_class_string(hsr)); - BUG(); - } - return arm_exit_handlers[hsr_ec]; } -- cgit v1.2.3 From 7af4df85796589e60a2dfc0f821eca0c4bbce4d2 Mon Sep 17 00:00:00 2001 From: Linu Cherian Date: Wed, 8 Mar 2017 11:38:33 +0530 Subject: KVM: arm/arm64: Enable KVM_CAP_NR_MEMSLOTS on arm/arm64 Return KVM_USER_MEM_SLOTS for userspace capability query on NR_MEMSLOTS. Reviewed-by: Christoffer Dall Signed-off-by: Linu Cherian Signed-off-by: Marc Zyngier --- arch/arm/kvm/arm.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch') diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index c9a2103faeb9..96dba7cd8be7 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -221,6 +221,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_MAX_VCPUS: r = KVM_MAX_VCPUS; break; + case KVM_CAP_NR_MEMSLOTS: + r = KVM_USER_MEM_SLOTS; + break; case KVM_CAP_MSI_DEVID: if (!kvm) r = -EINVAL; -- cgit v1.2.3 From 3e92f94a3b8e925a6dd7ec88a5794b2084b5fb65 Mon Sep 17 00:00:00 2001 From: Linu Cherian Date: Wed, 8 Mar 2017 11:38:34 +0530 Subject: KVM: arm/arm64: Remove KVM_PRIVATE_MEM_SLOTS definition that are unused arm/arm64 architecture doesnt use private memslots, hence removing KVM_PRIVATE_MEM_SLOTS macro definition. Reviewed-by: Christoffer Dall Signed-off-by: Linu Cherian Signed-off-by: Marc Zyngier --- arch/arm/include/asm/kvm_host.h | 1 - arch/arm64/include/asm/kvm_host.h | 1 - 2 files changed, 2 deletions(-) (limited to 'arch') diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index cc495d799c67..31ee468ce667 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -30,7 +30,6 @@ #define __KVM_HAVE_ARCH_INTC_INITIALIZED #define KVM_USER_MEM_SLOTS 32 -#define KVM_PRIVATE_MEM_SLOTS 4 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1 #define KVM_HAVE_ONE_REG #define KVM_HALT_POLL_NS_DEFAULT 500000 diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index f21fd3894370..6ac17ee887c9 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -31,7 +31,6 @@ #define __KVM_HAVE_ARCH_INTC_INITIALIZED #define KVM_USER_MEM_SLOTS 32 -#define KVM_PRIVATE_MEM_SLOTS 4 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1 #define KVM_HALT_POLL_NS_DEFAULT 500000 -- cgit v1.2.3 From 955a3fc6d2a1c11d6d00bce4f3816100ce0530cf Mon Sep 17 00:00:00 2001 From: Linu Cherian Date: Wed, 8 Mar 2017 11:38:35 +0530 Subject: KVM: arm64: Increase number of user memslots to 512 Having only 32 memslots is a real constraint for the maximum number of PCI devices that can be assigned to a single guest. Assuming each PCI device/virtual function having two memory BAR regions, we could assign only 15 devices/virtual functions to a guest. Hence increase KVM_USER_MEM_SLOTS to 512 as done in other archs like powerpc. Reviewed-by: Christoffer Dall Signed-off-by: Linu Cherian Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/kvm_host.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 6ac17ee887c9..e7705e7bb07b 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -30,7 +30,7 @@ #define __KVM_HAVE_ARCH_INTC_INITIALIZED -#define KVM_USER_MEM_SLOTS 32 +#define KVM_USER_MEM_SLOTS 512 #define KVM_COALESCED_MMIO_PAGE_OFFSET 1 #define KVM_HALT_POLL_NS_DEFAULT 500000 -- cgit v1.2.3