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-rw-r--r--arch/arm64/kvm/Kconfig1
-rw-r--r--arch/arm64/kvm/Makefile2
-rw-r--r--arch/arm64/kvm/fpsimd.c111
-rw-r--r--arch/arm64/kvm/hyp/switch.c51
4 files changed, 138 insertions, 27 deletions
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index a2e3a5af1113..47b23bf617c7 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -39,6 +39,7 @@ config KVM
select HAVE_KVM_IRQ_ROUTING
select IRQ_BYPASS_MANAGER
select HAVE_KVM_IRQ_BYPASS
+ select HAVE_KVM_VCPU_RUN_PID_CHANGE
---help---
Support hosting virtualized guest machines.
We don't support KVM with 16K page tables yet, due to the multiple
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index 93afff91cb7c..0f2a135ba15b 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -19,7 +19,7 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/psci.o $(KVM)/arm/perf.o
kvm-$(CONFIG_KVM_ARM_HOST) += inject_fault.o regmap.o va_layout.o
kvm-$(CONFIG_KVM_ARM_HOST) += hyp.o hyp-init.o handle_exit.o
kvm-$(CONFIG_KVM_ARM_HOST) += guest.o debug.o reset.o sys_regs.o sys_regs_generic_v8.o
-kvm-$(CONFIG_KVM_ARM_HOST) += vgic-sys-reg-v3.o
+kvm-$(CONFIG_KVM_ARM_HOST) += vgic-sys-reg-v3.o fpsimd.o
kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/aarch32.o
kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic.o
diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
new file mode 100644
index 000000000000..365933a98a7c
--- /dev/null
+++ b/arch/arm64/kvm/fpsimd.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * arch/arm64/kvm/fpsimd.c: Guest/host FPSIMD context coordination helpers
+ *
+ * Copyright 2018 Arm Limited
+ * Author: Dave Martin <Dave.Martin@arm.com>
+ */
+#include <linux/bottom_half.h>
+#include <linux/sched.h>
+#include <linux/thread_info.h>
+#include <linux/kvm_host.h>
+#include <asm/kvm_asm.h>
+#include <asm/kvm_host.h>
+#include <asm/kvm_mmu.h>
+
+/*
+ * Called on entry to KVM_RUN unless this vcpu previously ran at least
+ * once and the most recent prior KVM_RUN for this vcpu was called from
+ * the same task as current (highly likely).
+ *
+ * This is guaranteed to execute before kvm_arch_vcpu_load_fp(vcpu),
+ * such that on entering hyp the relevant parts of current are already
+ * mapped.
+ */
+int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu)
+{
+ int ret;
+
+ struct thread_info *ti = &current->thread_info;
+ struct user_fpsimd_state *fpsimd = &current->thread.uw.fpsimd_state;
+
+ /*
+ * Make sure the host task thread flags and fpsimd state are
+ * visible to hyp:
+ */
+ ret = create_hyp_mappings(ti, ti + 1, PAGE_HYP);
+ if (ret)
+ goto error;
+
+ ret = create_hyp_mappings(fpsimd, fpsimd + 1, PAGE_HYP);
+ if (ret)
+ goto error;
+
+ vcpu->arch.host_thread_info = kern_hyp_va(ti);
+ vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);
+error:
+ return ret;
+}
+
+/*
+ * Prepare vcpu for saving the host's FPSIMD state and loading the guest's.
+ * The actual loading is done by the FPSIMD access trap taken to hyp.
+ *
+ * Here, we just set the correct metadata to indicate that the FPSIMD
+ * state in the cpu regs (if any) belongs to current on the host.
+ *
+ * TIF_SVE is backed up here, since it may get clobbered with guest state.
+ * This flag is restored by kvm_arch_vcpu_put_fp(vcpu).
+ */
+void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu)
+{
+ BUG_ON(system_supports_sve());
+ BUG_ON(!current->mm);
+
+ vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED | KVM_ARM64_HOST_SVE_IN_USE);
+ vcpu->arch.flags |= KVM_ARM64_FP_HOST;
+ if (test_thread_flag(TIF_SVE))
+ vcpu->arch.flags |= KVM_ARM64_HOST_SVE_IN_USE;
+}
+
+/*
+ * If the guest FPSIMD state was loaded, update the host's context
+ * tracking data mark the CPU FPSIMD regs as dirty and belonging to vcpu
+ * so that they will be written back if the kernel clobbers them due to
+ * kernel-mode NEON before re-entry into the guest.
+ */
+void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu)
+{
+ WARN_ON_ONCE(!irqs_disabled());
+
+ if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) {
+ fpsimd_bind_state_to_cpu(&vcpu->arch.ctxt.gp_regs.fp_regs);
+ clear_thread_flag(TIF_FOREIGN_FPSTATE);
+ clear_thread_flag(TIF_SVE);
+ }
+}
+
+/*
+ * Write back the vcpu FPSIMD regs if they are dirty, and invalidate the
+ * cpu FPSIMD regs so that they can't be spuriously reused if this vcpu
+ * disappears and another task or vcpu appears that recycles the same
+ * struct fpsimd_state.
+ */
+void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
+{
+ local_bh_disable();
+
+ update_thread_flag(TIF_SVE,
+ vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE);
+
+ if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) {
+ /* Clean guest FP state to memory and invalidate cpu view */
+ fpsimd_save();
+ fpsimd_flush_cpu_state();
+ } else if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) {
+ /* Ensure user trap controls are correctly restored */
+ fpsimd_bind_task_to_cpu();
+ }
+
+ local_bh_enable();
+}
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index c0796c4d93a5..118f3002b9ce 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -23,19 +23,21 @@
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>
+#include <asm/kvm_host.h>
#include <asm/kvm_hyp.h>
#include <asm/kvm_mmu.h>
#include <asm/fpsimd.h>
#include <asm/debug-monitors.h>
+#include <asm/thread_info.h>
-static bool __hyp_text __fpsimd_enabled_nvhe(void)
+/* Check whether the FP regs were dirtied while in the host-side run loop: */
+static bool __hyp_text update_fp_enabled(struct kvm_vcpu *vcpu)
{
- return !(read_sysreg(cptr_el2) & CPTR_EL2_TFP);
-}
+ if (vcpu->arch.host_thread_info->flags & _TIF_FOREIGN_FPSTATE)
+ vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED |
+ KVM_ARM64_FP_HOST);
-static bool fpsimd_enabled_vhe(void)
-{
- return !!(read_sysreg(cpacr_el1) & CPACR_EL1_FPEN);
+ return !!(vcpu->arch.flags & KVM_ARM64_FP_ENABLED);
}
/* Save the 32-bit only FPSIMD system register state */
@@ -92,7 +94,10 @@ static void activate_traps_vhe(struct kvm_vcpu *vcpu)
val = read_sysreg(cpacr_el1);
val |= CPACR_EL1_TTA;
- val &= ~(CPACR_EL1_FPEN | CPACR_EL1_ZEN);
+ val &= ~CPACR_EL1_ZEN;
+ if (!update_fp_enabled(vcpu))
+ val &= ~CPACR_EL1_FPEN;
+
write_sysreg(val, cpacr_el1);
write_sysreg(kvm_get_hyp_vector(), vbar_el1);
@@ -105,7 +110,10 @@ static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu)
__activate_traps_common(vcpu);
val = CPTR_EL2_DEFAULT;
- val |= CPTR_EL2_TTA | CPTR_EL2_TFP | CPTR_EL2_TZ;
+ val |= CPTR_EL2_TTA | CPTR_EL2_TZ;
+ if (!update_fp_enabled(vcpu))
+ val |= CPTR_EL2_TFP;
+
write_sysreg(val, cptr_el2);
}
@@ -321,8 +329,6 @@ static bool __hyp_text __skip_instr(struct kvm_vcpu *vcpu)
void __hyp_text __hyp_switch_fpsimd(u64 esr __always_unused,
struct kvm_vcpu *vcpu)
{
- kvm_cpu_context_t *host_ctxt;
-
if (has_vhe())
write_sysreg(read_sysreg(cpacr_el1) | CPACR_EL1_FPEN,
cpacr_el1);
@@ -332,14 +338,19 @@ void __hyp_text __hyp_switch_fpsimd(u64 esr __always_unused,
isb();
- host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
- __fpsimd_save_state(&host_ctxt->gp_regs.fp_regs);
+ if (vcpu->arch.flags & KVM_ARM64_FP_HOST) {
+ __fpsimd_save_state(vcpu->arch.host_fpsimd_state);
+ vcpu->arch.flags &= ~KVM_ARM64_FP_HOST;
+ }
+
__fpsimd_restore_state(&vcpu->arch.ctxt.gp_regs.fp_regs);
/* Skip restoring fpexc32 for AArch64 guests */
if (!(read_sysreg(hcr_el2) & HCR_RW))
write_sysreg(vcpu->arch.ctxt.sys_regs[FPEXC32_EL2],
fpexc32_el2);
+
+ vcpu->arch.flags |= KVM_ARM64_FP_ENABLED;
}
/*
@@ -418,7 +429,6 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *host_ctxt;
struct kvm_cpu_context *guest_ctxt;
- bool fp_enabled;
u64 exit_code;
host_ctxt = vcpu->arch.host_cpu_context;
@@ -440,19 +450,14 @@ int kvm_vcpu_run_vhe(struct kvm_vcpu *vcpu)
/* And we're baaack! */
} while (fixup_guest_exit(vcpu, &exit_code));
- fp_enabled = fpsimd_enabled_vhe();
-
sysreg_save_guest_state_vhe(guest_ctxt);
__deactivate_traps(vcpu);
sysreg_restore_host_state_vhe(host_ctxt);
- if (fp_enabled) {
- __fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs);
- __fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs);
+ if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED)
__fpsimd_save_fpexc32(vcpu);
- }
__debug_switch_to_host(vcpu);
@@ -464,7 +469,6 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
{
struct kvm_cpu_context *host_ctxt;
struct kvm_cpu_context *guest_ctxt;
- bool fp_enabled;
u64 exit_code;
vcpu = kern_hyp_va(vcpu);
@@ -496,8 +500,6 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
/* And we're baaack! */
} while (fixup_guest_exit(vcpu, &exit_code));
- fp_enabled = __fpsimd_enabled_nvhe();
-
__sysreg_save_state_nvhe(guest_ctxt);
__sysreg32_save_state(vcpu);
__timer_disable_traps(vcpu);
@@ -508,11 +510,8 @@ int __hyp_text __kvm_vcpu_run_nvhe(struct kvm_vcpu *vcpu)
__sysreg_restore_state_nvhe(host_ctxt);
- if (fp_enabled) {
- __fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs);
- __fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs);
+ if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED)
__fpsimd_save_fpexc32(vcpu);
- }
/*
* This must come after restoring the host sysregs, since a non-VHE
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-04 17:29:45 +0000