Create a helper to do the guest va->pa mapping. Then take the code out of the
exit path, and use normal C.
copy_from_guest_va() is a bit more generic than it needs to be, but
not much.
Signed-off-by: Rusty Russell <rusty.russell@xxxxxxxxxx>
diff --git a/arch/arm/include/asm/kvm_asm.h b/arch/arm/include/asm/kvm_asm.h
index 85bd676..ee21cd2 100644
--- a/arch/arm/include/asm/kvm_asm.h
+++ b/arch/arm/include/asm/kvm_asm.h
@@ -54,6 +54,8 @@ extern void __kvm_flush_vm_context(void);
extern void __kvm_tlb_flush_vmid(struct kvm *kvm);
extern int __kvm_vcpu_run(struct kvm_vcpu *vcpu);
+
+extern u64 __kvm_va_to_pa(struct kvm_vcpu *vcpu, u32 va, bool priv);
#endif
#endif /* __ARM_KVM_ASM_H__ */
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 778d2af..79b5318 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -131,9 +131,6 @@ struct kvm_vcpu_arch {
u32 hdfar; /* Hyp Data Fault Address Register */
u32 hifar; /* Hyp Inst. Fault Address Register */
u32 hpfar; /* Hyp IPA Fault Address Register */
- u64 pc_ipa; /* IPA for the current PC (VA to PA result) */
- u64 pc_ipa2; /* same as above, but for non-aligned wide thumb
- instructions */
/* Floating point registers (VFP and Advanced SIMD/NEON) */
struct vfp_hard_struct vfp_guest;
diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
index aca6c2c..bb18fd4 100644
--- a/arch/arm/kernel/asm-offsets.c
+++ b/arch/arm/kernel/asm-offsets.c
@@ -184,8 +184,6 @@ int main(void)
DEFINE(VCPU_HDFAR, offsetof(struct kvm_vcpu, arch.hdfar));
DEFINE(VCPU_HIFAR, offsetof(struct kvm_vcpu, arch.hifar));
DEFINE(VCPU_HPFAR, offsetof(struct kvm_vcpu, arch.hpfar));
- DEFINE(VCPU_PC_IPA, offsetof(struct kvm_vcpu, arch.pc_ipa));
- DEFINE(VCPU_PC_IPA2, offsetof(struct kvm_vcpu, arch.pc_ipa2));
DEFINE(VCPU_HYP_PC, offsetof(struct kvm_vcpu, arch.hyp_pc));
DEFINE(KVM_VTTBR, offsetof(struct kvm, arch.vttbr));
#endif
diff --git a/arch/arm/kvm/interrupts.S b/arch/arm/kvm/interrupts.S
index b70394a..d282860 100644
--- a/arch/arm/kvm/interrupts.S
+++ b/arch/arm/kvm/interrupts.S
@@ -510,6 +510,37 @@ after_vfp_restore:
clrex @ Clear exclusive monitor
bx lr @ return to IOCTL
+@ Arguments:
+@ r0: pointer to vcpu struct
+@ r1: virtual address to map (rounded to page)
+@ r2: 1 = P1 (read) mapping, 0 = P0 (read) mapping.
+@ Returns 64 bit PAR value.
+ENTRY(__kvm_va_to_pa)
+ hvc #0 @ switch to hyp-mode
+
+ push {r4-r12}
+
+ @ Fold flag into r1, easier than using stack.
+ orr r1, r1, r2
+
+ @ This swaps too many registers, but we're in the slow path anyway.
+ read_cp15_state
+ write_cp15_state 1, r0
+
+ ands r2, r1, #1
+ sub r1, r1, r2
+ mcrne p15, 0, r1, c7, c8, 0 @ VA to PA, ATS1CPR
+ mcreq p15, 0, r1, c7, c8, 2 @ VA to PA, ATS1CUR
+
+ @ Restore host state.
+ read_cp15_state 1, r0
+ write_cp15_state
+
+ mrrc p15, 0, r0, r1, c7 @ PAR
+ pop {r4-r12}
+ hvc #0 @ Back to SVC
+ bx lr
+
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ Hypervisor exception vector and handlers
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@@ -686,34 +717,6 @@ guest_trap:
cmpne r2, #HSR_EC_DABT
bne 1f
- @ For non-valid data aborts, get the offending instr. PA
- lsr r2, r0, #HSR_ISV_SHIFT
- ands r2, r2, #1
- bne 2f
- mrs r3, ELR_hyp
- mrs r7, spsr
- and r7, r7, #0xf
- cmp r7, #0 @ fault happened in user mode?
- mcreq p15, 0, r3, c7, c8, 2 @ VA to PA, ATS1CUR
- mcrne p15, 0, r3, c7, c8, 0 @ VA to PA, ATS1CPR
- mrrc p15, 0, r4, r5, c7 @ PAR
- add r6, r1, #VCPU_PC_IPA
- strd r4, r5, [r6]
-
- @ Check if we might have a wide thumb instruction spill-over
- ldr r5, =0xfff
- bic r4, r3, r5 @ clear page mask
- sub r5, r5, #1 @ last 2-byte page bounday, 0xffe
- cmp r4, r5
- bne 2f
- add r4, r3, #2 @ _really_ unlikely!
- cmp r7, #0 @ fault happened in user mode?
- mcreq p15, 0, r4, c7, c8, 2 @ VA to PA, ATS1CUR
- mcrne p15, 0, r4, c7, c8, 0 @ VA to PA, ATS1CPR
- mrrc p15, 0, r4, r5, c7 @ PAR
- add r6, r1, #VCPU_PC_IPA2
- strd r4, r5, [r6]
-
2: mrc p15, 4, r2, c6, c0, 0 @ HDFAR
mrc p15, 4, r3, c6, c0, 2 @ HIFAR
mrc p15, 4, r4, c6, c0, 4 @ HPFAR
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 3df4fa8..6909a83 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -580,6 +580,62 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
}
/**
+ * copy_from_guest_va - copy memory from guest (very slow!)
+ * @vcpu: vcpu pointer
+ * @dest: memory to copy into
+ * @va: virtual address in guest to copy from
+ * @len: length to copy
+ * @priv: use guest PL1 (ie. kernel) mappings, otherwise use guest PL0 mappings.
+ *
+ * Returns 0 on success, or errno.
+ */
+static int copy_from_guest_va(struct kvm_vcpu *vcpu,
+ void *dest, unsigned long va, size_t len,
+ bool priv)
+{
+ u64 par;
+ phys_addr_t pc_ipa;
+ size_t cur_len;
+ int err;
+
+ /* A 32-bit thumb2 instruction can actually go over a page boundary! */
+ do {
+ par = __kvm_va_to_pa(vcpu, va & PAGE_MASK, priv);
+ if (par & 1) {
+ kvm_err("I/O Abort from invalid instruction address? Wrong!\n");
+ return -EINVAL;
+ }
+
+ if (par & (1U << 11)) {
+ /* LPAE PAR format */
+ /*
+ * TODO: Check if this ever happens
+ * - called from Hyp mode
+ */
+ pc_ipa = par & PAGE_MASK & ((1ULL << 32) - 1);
+ } else {
+ /* VMSAv7 PAR format */
+ pc_ipa = par & PAGE_MASK & ((1ULL << 40) - 1);
+ }
+ pc_ipa += va & ~PAGE_MASK;
+
+ /* Only copy up to end of page. */
+ cur_len = (pc_ipa & PAGE_MASK) + PAGE_SIZE - pc_ipa;
+ if (likely(cur_len > len))
+ cur_len = len;
+
+ err = kvm_read_guest(vcpu->kvm, pc_ipa, dest, cur_len);
+ if (unlikely(err))
+ return err;
+
+ len -= cur_len;
+ va += cur_len;
+ } while (unlikely(len != 0));
+
+ return 0;
+}
+
+/**
* invalid_io_mem_abort -- Handle I/O aborts ISV bit is clear
*
* @vcpu: The vcpu pointer
@@ -593,22 +649,7 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
static int invalid_io_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
{
unsigned long instr;
- phys_addr_t pc_ipa;
-
- if (vcpu->arch.pc_ipa & 1) {
- kvm_err("I/O Abort from invalid instruction address? Wrong!\n");
- return -EINVAL;
- }
-
- if (vcpu->arch.pc_ipa & (1U << 11)) {
- /* LPAE PAR format */
- /* TODO: Check if this ever happens - called from Hyp mode */
- pc_ipa = vcpu->arch.pc_ipa & PAGE_MASK & ((1ULL << 32) - 1);
- } else {
- /* VMSAv7 PAR format */
- pc_ipa = vcpu->arch.pc_ipa & PAGE_MASK & ((1ULL << 40) - 1);
- }
- pc_ipa += vcpu->arch.regs.pc & ~PAGE_MASK;
+ int err;
if (vcpu->arch.regs.cpsr & PSR_T_BIT) {
/* TODO: Check validity of PC IPA and IPA2!!! */
@@ -617,9 +658,11 @@ static int invalid_io_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
return -EINVAL;
}
- if (kvm_read_guest(vcpu->kvm, pc_ipa, &instr, sizeof(instr))) {
+ err = copy_from_guest_va(vcpu, &instr, vcpu->arch.regs.pc, sizeof(instr),
+ vcpu_mode_priv(vcpu));
+ if (err) {
kvm_err("Could not copy guest instruction\n");
- return -EFAULT;
+ return err;
}
return kvm_emulate_mmio_ls(vcpu, fault_ipa, instr);
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