Commit 2d761dbf authored by Marc Zyngier's avatar Marc Zyngier
Browse files

Merge branch kvm-arm64/fpsimd-tracking into kvmarm-master/next 



* kvm-arm64/fpsimd-tracking:
  : .
  : Simplify the handling of both the FP/SIMD and SVE state by
  : removing the need for mapping the thread at EL2, and by
  : dropping the tracking of the host's SVE state which is
  : always invalid by construction.
  : .
  arm64/fpsimd: Document the use of TIF_FOREIGN_FPSTATE by KVM
  KVM: arm64: Stop mapping current thread_info at EL2
  KVM: arm64: Introduce flag shadowing TIF_FOREIGN_FPSTATE
  KVM: arm64: Remove unused __sve_save_state
  KVM: arm64: Get rid of host SVE tracking/saving
  KVM: arm64: Reorder vcpu flag definitions

Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parents e525523c 31aa126d

arch/arm64/include/asm/kvm_host.h

+14 −15
Original line number Diff line number Diff line
@@ -26,7 +26,6 @@ 
#include <asm/fpsimd.h>

#include <asm/kvm.h>

#include <asm/kvm_asm.h>

#include <asm/thread_info.h>



#define __KVM_HAVE_ARCH_INTC_INITIALIZED
@@ -321,7 +320,6 @@ struct kvm_vcpu_arch { 
	struct kvm_guest_debug_arch vcpu_debug_state;

	struct kvm_guest_debug_arch external_debug_state;



	struct thread_info *host_thread_info;	/* hyp VA */

	struct user_fpsimd_state *host_fpsimd_state;	/* hyp VA */



	struct {
@@ -408,20 +406,17 @@ struct kvm_vcpu_arch { 
#define KVM_ARM64_DEBUG_DIRTY		(1 << 0)

#define KVM_ARM64_FP_ENABLED		(1 << 1) /* guest FP regs loaded */

#define KVM_ARM64_FP_HOST		(1 << 2) /* host FP regs loaded */

#define KVM_ARM64_HOST_SVE_IN_USE	(1 << 3) /* backup for host TIF_SVE */

#define KVM_ARM64_HOST_SVE_ENABLED	(1 << 4) /* SVE enabled for EL0 */

#define KVM_ARM64_GUEST_HAS_SVE		(1 << 5) /* SVE exposed to guest */

#define KVM_ARM64_VCPU_SVE_FINALIZED	(1 << 6) /* SVE config completed */

#define KVM_ARM64_GUEST_HAS_PTRAUTH	(1 << 7) /* PTRAUTH exposed to guest */

#define KVM_ARM64_PENDING_EXCEPTION	(1 << 8) /* Exception pending */

/*

 * Overlaps with KVM_ARM64_EXCEPT_MASK on purpose so that it can't be

 * set together with an exception...

 */

#define KVM_ARM64_INCREMENT_PC		(1 << 9) /* Increment PC */

#define KVM_ARM64_EXCEPT_MASK		(7 << 9) /* Target EL/MODE */

#define KVM_ARM64_DEBUG_STATE_SAVE_SPE	(1 << 12) /* Save SPE context if active  */

#define KVM_ARM64_DEBUG_STATE_SAVE_TRBE	(1 << 13) /* Save TRBE context if active  */



#define KVM_GUESTDBG_VALID_MASK (KVM_GUESTDBG_ENABLE | \

				 KVM_GUESTDBG_USE_SW_BP | \

				 KVM_GUESTDBG_USE_HW | \

				 KVM_GUESTDBG_SINGLESTEP)

/*

 * When KVM_ARM64_PENDING_EXCEPTION is set, KVM_ARM64_EXCEPT_MASK can

 * take the following values:
@@ -439,11 +434,14 @@ struct kvm_vcpu_arch { 
#define KVM_ARM64_EXCEPT_AA64_EL1	(0 << 11)

#define KVM_ARM64_EXCEPT_AA64_EL2	(1 << 11)



/*

 * Overlaps with KVM_ARM64_EXCEPT_MASK on purpose so that it can't be

 * set together with an exception...

 */

#define KVM_ARM64_INCREMENT_PC		(1 << 9) /* Increment PC */

#define KVM_ARM64_DEBUG_STATE_SAVE_SPE	(1 << 12) /* Save SPE context if active  */

#define KVM_ARM64_DEBUG_STATE_SAVE_TRBE	(1 << 13) /* Save TRBE context if active  */

#define KVM_ARM64_FP_FOREIGN_FPSTATE	(1 << 14)



#define KVM_GUESTDBG_VALID_MASK (KVM_GUESTDBG_ENABLE | \

				 KVM_GUESTDBG_USE_SW_BP | \

				 KVM_GUESTDBG_USE_HW | \

				 KVM_GUESTDBG_SINGLESTEP)



#define vcpu_has_sve(vcpu) (system_supports_sve() &&			\

			    ((vcpu)->arch.flags & KVM_ARM64_GUEST_HAS_SVE))
@@ -736,6 +734,7 @@ long kvm_vm_ioctl_mte_copy_tags(struct kvm *kvm, 
/* Guest/host FPSIMD coordination helpers */

int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu);

void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu);

void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu);

void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu);

void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu);

arch/arm64/include/asm/kvm_hyp.h

+0 −1
Original line number Diff line number Diff line
@@ -90,7 +90,6 @@ void __debug_restore_host_buffers_nvhe(struct kvm_vcpu *vcpu); 


void __fpsimd_save_state(struct user_fpsimd_state *fp_regs);

void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs);

void __sve_save_state(void *sve_pffr, u32 *fpsr);

void __sve_restore_state(void *sve_pffr, u32 *fpsr);



#ifndef __KVM_NVHE_HYPERVISOR__

arch/arm64/kernel/fpsimd.c

+5 −1
Original line number Diff line number Diff line
@@ -78,7 +78,11 @@ 
 * indicate whether or not the userland FPSIMD state of the current task is

 * present in the registers. The flag is set unless the FPSIMD registers of this

 * CPU currently contain the most recent userland FPSIMD state of the current

 * task.

 * task. If the task is behaving as a VMM, then this is will be managed by

 * KVM which will clear it to indicate that the vcpu FPSIMD state is currently

 * loaded on the CPU, allowing the state to be saved if a FPSIMD-aware

 * softirq kicks in. Upon vcpu_put(), KVM will save the vcpu FP state and

 * flag the register state as invalid.

 *

 * In order to allow softirq handlers to use FPSIMD, kernel_neon_begin() may

 * save the task's FPSIMD context back to task_struct from softirq context.

arch/arm64/kvm/arm.c

+1 −0
Original line number Diff line number Diff line
@@ -856,6 +856,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) 
		}



		kvm_arm_setup_debug(vcpu);

		kvm_arch_vcpu_ctxflush_fp(vcpu);



		/**************************************************************

		 * Enter the guest

arch/arm64/kvm/fpsimd.c

+16 −30
Original line number Diff line number Diff line
@@ -7,7 +7,6 @@ 
 */

#include <linux/irqflags.h>

#include <linux/sched.h>

#include <linux/thread_info.h>

#include <linux/kvm_host.h>

#include <asm/fpsimd.h>

#include <asm/kvm_asm.h>
@@ -28,24 +27,13 @@ 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;



	/* Make sure the host task fpsimd state is visible to hyp: */

	ret = create_hyp_mappings(fpsimd, fpsimd + 1, PAGE_HYP);

	if (ret)

		goto error;



	vcpu->arch.host_thread_info = kern_hyp_va(ti);

	if (!ret)

		vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);

error:



	return ret;

}
@@ -55,26 +43,27 @@ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu) 
 *

 * 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(!current->mm);

	BUG_ON(test_thread_flag(TIF_SVE));



	vcpu->arch.flags &= ~(KVM_ARM64_FP_ENABLED |

			      KVM_ARM64_HOST_SVE_IN_USE |

			      KVM_ARM64_HOST_SVE_ENABLED);

	vcpu->arch.flags &= ~KVM_ARM64_FP_ENABLED;

	vcpu->arch.flags |= KVM_ARM64_FP_HOST;



	if (test_thread_flag(TIF_SVE))

		vcpu->arch.flags |= KVM_ARM64_HOST_SVE_IN_USE;



	if (read_sysreg(cpacr_el1) & CPACR_EL1_ZEN_EL0EN)

		vcpu->arch.flags |= KVM_ARM64_HOST_SVE_ENABLED;

}



void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu)

{

	if (test_thread_flag(TIF_FOREIGN_FPSTATE))

		vcpu->arch.flags |= KVM_ARM64_FP_FOREIGN_FPSTATE;

	else

		vcpu->arch.flags &= ~KVM_ARM64_FP_FOREIGN_FPSTATE;

}



/*

 * 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
@@ -104,13 +93,11 @@ void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu) 
void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)

{

	unsigned long flags;

	bool host_has_sve = system_supports_sve();

	bool guest_has_sve = vcpu_has_sve(vcpu);



	local_irq_save(flags);



	if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) {

		if (guest_has_sve) {

		if (vcpu_has_sve(vcpu)) {

			__vcpu_sys_reg(vcpu, ZCR_EL1) = read_sysreg_el1(SYS_ZCR);



			/* Restore the VL that was saved when bound to the CPU */
@@ -120,7 +107,7 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) 
		}



		fpsimd_save_and_flush_cpu_state();

	} else if (has_vhe() && host_has_sve) {

	} else if (has_vhe() && system_supports_sve()) {

		/*

		 * The FPSIMD/SVE state in the CPU has not been touched, and we

		 * have SVE (and VHE): CPACR_EL1 (alias CPTR_EL2) has been
@@ -134,8 +121,7 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) 
			sysreg_clear_set(CPACR_EL1, CPACR_EL1_ZEN_EL0EN, 0);

	}



	update_thread_flag(TIF_SVE,

			   vcpu->arch.flags & KVM_ARM64_HOST_SVE_IN_USE);

	update_thread_flag(TIF_SVE, 0);



	local_irq_restore(flags);

}