[PATCH v3 06/18] KVM: arm64: nVHE: Use separate vector for the host
Andrew Scull
ascull at google.com
Thu Sep 3 09:52:55 EDT 2020
The host is treated differently from the guests when an exception is
taken so introduce a separate vector that is specialized for the host.
This also allows the nVHE specific code to move out of hyp-entry.S and
into nvhe/host.S.
The host is only expected to make HVC calls and anything else is
considered invalid and results in a panic.
Hyp initialization is now passed the vector that is used for the host
and it is swapped for the guest vector during the context switch.
Signed-off-by: Andrew Scull <ascull at google.com>
---
arch/arm64/include/asm/kvm_asm.h | 2 +
arch/arm64/kernel/image-vars.h | 1 +
arch/arm64/kvm/arm.c | 11 +++-
arch/arm64/kvm/hyp/hyp-entry.S | 66 --------------------
arch/arm64/kvm/hyp/nvhe/Makefile | 2 +-
arch/arm64/kvm/hyp/nvhe/host.S | 104 +++++++++++++++++++++++++++++++
arch/arm64/kvm/hyp/nvhe/switch.c | 3 +
7 files changed, 121 insertions(+), 68 deletions(-)
create mode 100644 arch/arm64/kvm/hyp/nvhe/host.S
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 6f9c4162a764..34ec1b558219 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -98,10 +98,12 @@ struct kvm_vcpu;
struct kvm_s2_mmu;
DECLARE_KVM_NVHE_SYM(__kvm_hyp_init);
+DECLARE_KVM_NVHE_SYM(__kvm_hyp_host_vector);
DECLARE_KVM_HYP_SYM(__kvm_hyp_vector);
#ifndef __KVM_NVHE_HYPERVISOR__
#define __kvm_hyp_init CHOOSE_NVHE_SYM(__kvm_hyp_init)
+#define __kvm_hyp_host_vector CHOOSE_NVHE_SYM(__kvm_hyp_host_vector)
#define __kvm_hyp_vector CHOOSE_HYP_SYM(__kvm_hyp_vector)
#endif
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index 8982b68289b7..54bb0eb34b0f 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -71,6 +71,7 @@ KVM_NVHE_ALIAS(kvm_update_va_mask);
/* Global kernel state accessed by nVHE hyp code. */
KVM_NVHE_ALIAS(arm64_ssbd_callback_required);
KVM_NVHE_ALIAS(kvm_host_data);
+KVM_NVHE_ALIAS(kvm_hyp_vector);
KVM_NVHE_ALIAS(kvm_vgic_global_state);
/* Kernel constant needed to compute idmap addresses. */
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 77fc856ea513..b6442c6be5ad 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1277,7 +1277,7 @@ static void cpu_init_hyp_mode(void)
pgd_ptr = kvm_mmu_get_httbr();
hyp_stack_ptr = __this_cpu_read(kvm_arm_hyp_stack_page) + PAGE_SIZE;
- vector_ptr = __this_cpu_read(kvm_hyp_vector);
+ vector_ptr = (unsigned long)kern_hyp_va(kvm_ksym_ref(__kvm_hyp_host_vector));
/*
* Call initialization code, and switch to the full blown HYP code.
@@ -1542,6 +1542,7 @@ static int init_hyp_mode(void)
for_each_possible_cpu(cpu) {
struct kvm_host_data *cpu_data;
+ unsigned long *vector;
cpu_data = per_cpu_ptr(&kvm_host_data, cpu);
err = create_hyp_mappings(cpu_data, cpu_data + 1, PAGE_HYP);
@@ -1550,6 +1551,14 @@ static int init_hyp_mode(void)
kvm_err("Cannot map host CPU state: %d\n", err);
goto out_err;
}
+
+ vector = per_cpu_ptr(&kvm_hyp_vector, cpu);
+ err = create_hyp_mappings(vector, vector + 1, PAGE_HYP);
+
+ if (err) {
+ kvm_err("Cannot map hyp guest vector address\n");
+ goto out_err;
+ }
}
err = hyp_map_aux_data();
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S
index 9cb3fbca5d79..f92489250dfc 100644
--- a/arch/arm64/kvm/hyp/hyp-entry.S
+++ b/arch/arm64/kvm/hyp/hyp-entry.S
@@ -12,7 +12,6 @@
#include <asm/cpufeature.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_asm.h>
-#include <asm/kvm_mmu.h>
#include <asm/mmu.h>
.macro save_caller_saved_regs_vect
@@ -41,20 +40,6 @@
.text
-.macro do_el2_call
- /*
- * Shuffle the parameters before calling the function
- * pointed to in x0. Assumes parameters in x[1,2,3].
- */
- str lr, [sp, #-16]!
- mov lr, x0
- mov x0, x1
- mov x1, x2
- mov x2, x3
- blr lr
- ldr lr, [sp], #16
-.endm
-
el1_sync: // Guest trapped into EL2
mrs x0, esr_el2
@@ -63,44 +48,6 @@ el1_sync: // Guest trapped into EL2
ccmp x0, #ESR_ELx_EC_HVC32, #4, ne
b.ne el1_trap
-#ifdef __KVM_NVHE_HYPERVISOR__
- mrs x1, vttbr_el2 // If vttbr is valid, the guest
- cbnz x1, el1_hvc_guest // called HVC
-
- /* Here, we're pretty sure the host called HVC. */
- ldp x0, x1, [sp], #16
-
- /* Check for a stub HVC call */
- cmp x0, #HVC_STUB_HCALL_NR
- b.hs 1f
-
- /*
- * Compute the idmap address of __kvm_handle_stub_hvc and
- * jump there. Since we use kimage_voffset, do not use the
- * HYP VA for __kvm_handle_stub_hvc, but the kernel VA instead
- * (by loading it from the constant pool).
- *
- * Preserve x0-x4, which may contain stub parameters.
- */
- ldr x5, =__kvm_handle_stub_hvc
- ldr_l x6, kimage_voffset
-
- /* x5 = __pa(x5) */
- sub x5, x5, x6
- br x5
-
-1:
- /*
- * Perform the EL2 call
- */
- kern_hyp_va x0
- do_el2_call
-
- eret
- sb
-#endif /* __KVM_NVHE_HYPERVISOR__ */
-
-el1_hvc_guest:
/*
* Fastest possible path for ARM_SMCCC_ARCH_WORKAROUND_1.
* The workaround has already been applied on the host,
@@ -198,18 +145,6 @@ el2_error:
eret
sb
-#ifdef __KVM_NVHE_HYPERVISOR__
-SYM_FUNC_START(__hyp_do_panic)
- mov lr, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\
- PSR_MODE_EL1h)
- msr spsr_el2, lr
- ldr lr, =panic
- msr elr_el2, lr
- eret
- sb
-SYM_FUNC_END(__hyp_do_panic)
-#endif
-
.macro invalid_vector label, target = hyp_panic
.align 2
SYM_CODE_START(\label)
@@ -222,7 +157,6 @@ SYM_CODE_END(\label)
invalid_vector el2t_irq_invalid
invalid_vector el2t_fiq_invalid
invalid_vector el2t_error_invalid
- invalid_vector el2h_sync_invalid
invalid_vector el2h_irq_invalid
invalid_vector el2h_fiq_invalid
invalid_vector el1_fiq_invalid
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index aef76487edc2..ddf98eb07b9d 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -6,7 +6,7 @@
asflags-y := -D__KVM_NVHE_HYPERVISOR__
ccflags-y := -D__KVM_NVHE_HYPERVISOR__
-obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o
+obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o
obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \
../fpsimd.o ../hyp-entry.o
diff --git a/arch/arm64/kvm/hyp/nvhe/host.S b/arch/arm64/kvm/hyp/nvhe/host.S
new file mode 100644
index 000000000000..9c96b9a3b71d
--- /dev/null
+++ b/arch/arm64/kvm/hyp/nvhe/host.S
@@ -0,0 +1,104 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 - Google Inc
+ * Author: Andrew Scull <ascull at google.com>
+ */
+
+#include <linux/linkage.h>
+
+#include <asm/assembler.h>
+#include <asm/kvm_asm.h>
+#include <asm/kvm_mmu.h>
+
+ .text
+
+SYM_FUNC_START(__hyp_do_panic)
+ mov lr, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\
+ PSR_MODE_EL1h)
+ msr spsr_el2, lr
+ ldr lr, =panic
+ msr elr_el2, lr
+ eret
+ sb
+SYM_FUNC_END(__hyp_do_panic)
+
+.macro valid_host_el1_sync_vect
+ .align 7
+ esb
+ stp x0, x1, [sp, #-16]!
+
+ mrs x0, esr_el2
+ lsr x0, x0, #ESR_ELx_EC_SHIFT
+ cmp x0, #ESR_ELx_EC_HVC64
+ b.ne hyp_panic
+
+ ldp x0, x1, [sp], #16
+
+ /* Check for a stub HVC call */
+ cmp x0, #HVC_STUB_HCALL_NR
+ b.hs 1f
+
+ /*
+ * Compute the idmap address of __kvm_handle_stub_hvc and
+ * jump there. Since we use kimage_voffset, do not use the
+ * HYP VA for __kvm_handle_stub_hvc, but the kernel VA instead
+ * (by loading it from the constant pool).
+ *
+ * Preserve x0-x4, which may contain stub parameters.
+ */
+ ldr x5, =__kvm_handle_stub_hvc
+ ldr_l x6, kimage_voffset
+
+ /* x5 = __pa(x5) */
+ sub x5, x5, x6
+ br x5
+
+1:
+ /*
+ * Shuffle the parameters before calling the function
+ * pointed to in x0. Assumes parameters in x[1,2,3].
+ */
+ kern_hyp_va x0
+ str lr, [sp, #-16]!
+ mov lr, x0
+ mov x0, x1
+ mov x1, x2
+ mov x2, x3
+ blr lr
+ ldr lr, [sp], #16
+
+ eret
+ sb
+.endm
+
+.macro invalid_host_vect
+ .align 7
+ b hyp_panic
+.endm
+
+/*
+ * CONFIG_KVM_INDIRECT_VECTORS is not applied to the host vector because the
+ * host already knows the address of hyp by virtue of loading it there.
+ */
+ .align 11
+SYM_CODE_START(__kvm_hyp_host_vector)
+ invalid_host_vect // Synchronous EL2t
+ invalid_host_vect // IRQ EL2t
+ invalid_host_vect // FIQ EL2t
+ invalid_host_vect // Error EL2t
+
+ invalid_host_vect // Synchronous EL2h
+ invalid_host_vect // IRQ EL2h
+ invalid_host_vect // FIQ EL2h
+ invalid_host_vect // Error EL2h
+
+ valid_host_el1_sync_vect // Synchronous 64-bit EL1
+ invalid_host_vect // IRQ 64-bit EL1
+ invalid_host_vect // FIQ 64-bit EL1
+ invalid_host_vect // Error 64-bit EL1
+
+ invalid_host_vect // Synchronous 32-bit EL1
+ invalid_host_vect // IRQ 32-bit EL1
+ invalid_host_vect // FIQ 32-bit EL1
+ invalid_host_vect // Error 32-bit EL1
+SYM_CODE_END(__kvm_hyp_host_vector)
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index 1e8a31b7c94c..1ab773bb60ca 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -42,6 +42,7 @@ static void __activate_traps(struct kvm_vcpu *vcpu)
}
write_sysreg(val, cptr_el2);
+ write_sysreg(__hyp_this_cpu_read(kvm_hyp_vector), vbar_el2);
if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
struct kvm_cpu_context *ctxt = &vcpu->arch.ctxt;
@@ -60,6 +61,7 @@ static void __activate_traps(struct kvm_vcpu *vcpu)
static void __deactivate_traps(struct kvm_vcpu *vcpu)
{
+ extern char __kvm_hyp_host_vector[];
u64 mdcr_el2;
___deactivate_traps(vcpu);
@@ -91,6 +93,7 @@ static void __deactivate_traps(struct kvm_vcpu *vcpu)
write_sysreg(mdcr_el2, mdcr_el2);
write_sysreg(HCR_HOST_NVHE_FLAGS, hcr_el2);
write_sysreg(CPTR_EL2_DEFAULT, cptr_el2);
+ write_sysreg(__kvm_hyp_host_vector, vbar_el2);
}
static void __load_host_stage2(void)
--
2.28.0.402.g5ffc5be6b7-goog
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