Commit 4abc8108 authored by Marc Zyngier's avatar Marc Zyngier Committed by Junhao He
Browse files

KVM: arm64: Exclude FP ownership from kvm_vcpu_arch 

mainline inclusion
from mainline-v6.9-rc1
commit 5294afdbf45aced5295fe5941c58b40c41c23800
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8EC9K
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5294afdbf45aced5295fe5941c58b40c41c23800



--------------------------------

In retrospect, it is fairly obvious that the FP state ownership
is only meaningful for a given CPU, and that locating this
information in the vcpu was just a mistake.

Move the ownership tracking into the host data structure, and
rename it from fp_state to fp_owner, which is a better description
(name suggested by Mark Brown).

Reviewed-by: default avatarMark Brown <broonie@kernel.org>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Signed-off-by: default avatarJunhao He <hejunhao3@huawei.com>
parent 122733f3

arch/arm64/include/asm/kvm_emulate.h

+2 −2
Original line number Diff line number Diff line
@@ -616,7 +616,7 @@ static __always_inline u64 kvm_get_reset_cptr_el2(struct kvm_vcpu *vcpu) 
		val = (CPACR_EL1_FPEN_EL0EN | CPACR_EL1_FPEN_EL1EN);



		if (!vcpu_has_sve(vcpu) ||

		    (vcpu->arch.fp_state != FP_STATE_GUEST_OWNED))

		    (*host_data_ptr(fp_owner) != FP_STATE_GUEST_OWNED))

			val |= CPACR_EL1_ZEN_EL1EN | CPACR_EL1_ZEN_EL0EN;

		if (cpus_have_final_cap(ARM64_SME))

			val |= CPACR_EL1_SMEN_EL1EN | CPACR_EL1_SMEN_EL0EN;
@@ -624,7 +624,7 @@ static __always_inline u64 kvm_get_reset_cptr_el2(struct kvm_vcpu *vcpu) 
		val = CPTR_NVHE_EL2_RES1;



		if (vcpu_has_sve(vcpu) &&

		    (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED))

		    (*host_data_ptr(fp_owner) == FP_STATE_GUEST_OWNED))

			val |= CPTR_EL2_TZ;

		if (cpus_have_final_cap(ARM64_SME))

			val &= ~CPTR_EL2_TSM;

arch/arm64/include/asm/kvm_host.h

+7 −7
Original line number Diff line number Diff line
@@ -465,6 +465,13 @@ struct kvm_host_data { 
	struct kvm_cpu_context host_ctxt;

	struct user_fpsimd_state *fpsimd_state;	/* hyp VA */



	/* Ownership of the FP regs */

	enum {

		FP_STATE_FREE,

		FP_STATE_HOST_OWNED,

		FP_STATE_GUEST_OWNED,

	} fp_owner;



	/*

	 * host_debug_state contains the host registers which are

	 * saved and restored during world switches.
@@ -540,13 +547,6 @@ struct kvm_vcpu_arch { 
	/* Exception Information */

	struct kvm_vcpu_fault_info fault;



	/* Ownership of the FP regs */

	enum {

		FP_STATE_FREE,

		FP_STATE_HOST_OWNED,

		FP_STATE_GUEST_OWNED,

	} fp_state;



	/* Configuration flags, set once and for all before the vcpu can run */

	u8 cflags;

arch/arm64/kvm/arm.c

+0 −6
Original line number Diff line number Diff line
@@ -449,12 +449,6 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) 


	vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO;



	/*

	 * Default value for the FP state, will be overloaded at load

	 * time if we support FP (pretty likely)

	 */

	vcpu->arch.fp_state = FP_STATE_FREE;



	/* Set up the timer */

	kvm_timer_vcpu_init(vcpu);

arch/arm64/kvm/fpsimd.c

+5 −5
Original line number Diff line number Diff line
@@ -84,7 +84,7 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) 
	 * guest in kvm_arch_vcpu_ctxflush_fp() and override this to

	 * FP_STATE_FREE if the flag set.

	 */

	vcpu->arch.fp_state = FP_STATE_HOST_OWNED;

	*host_data_ptr(fp_owner) = FP_STATE_HOST_OWNED;

	*host_data_ptr(fpsimd_state) = kern_hyp_va(&current->thread.uw.fpsimd_state);



	vcpu_clear_flag(vcpu, HOST_SVE_ENABLED);
@@ -109,7 +109,7 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) 
		 * been saved, this is very unlikely to happen.

		 */

		if (read_sysreg_s(SYS_SVCR) & (SVCR_SM_MASK | SVCR_ZA_MASK)) {

			vcpu->arch.fp_state = FP_STATE_FREE;

			*host_data_ptr(fp_owner) = FP_STATE_FREE;

			fpsimd_save_and_flush_cpu_state();

		}

	}
@@ -125,7 +125,7 @@ void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu) 
void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu)

{

	if (test_thread_flag(TIF_FOREIGN_FPSTATE))

		vcpu->arch.fp_state = FP_STATE_FREE;

		*host_data_ptr(fp_owner) = FP_STATE_FREE;

}



/*
@@ -141,7 +141,7 @@ void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu) 


	WARN_ON_ONCE(!irqs_disabled());



	if (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED) {

	if (*host_data_ptr(fp_owner) == FP_STATE_GUEST_OWNED) {



		/*

		 * Currently we do not support SME guests so SVCR is
@@ -194,7 +194,7 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu) 
		isb();

	}



	if (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED) {

	if (*host_data_ptr(fp_owner) == FP_STATE_GUEST_OWNED) {

		if (vcpu_has_sve(vcpu)) {

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

arch/arm64/kvm/hyp/include/hyp/switch.h

+3 −3
Original line number Diff line number Diff line
@@ -42,7 +42,7 @@ extern struct kvm_exception_table_entry __stop___kvm_ex_table; 
/* Check whether the FP regs are owned by the guest */

static inline bool guest_owns_fp_regs(struct kvm_vcpu *vcpu)

{

	return vcpu->arch.fp_state == FP_STATE_GUEST_OWNED;

	return *host_data_ptr(fp_owner) == FP_STATE_GUEST_OWNED;

}



/* Save the 32-bit only FPSIMD system register state */
@@ -364,7 +364,7 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code) 
	isb();



	/* Write out the host state if it's in the registers */

	if (vcpu->arch.fp_state == FP_STATE_HOST_OWNED)

	if (*host_data_ptr(fp_owner) == FP_STATE_HOST_OWNED)

		__fpsimd_save_state(*host_data_ptr(fpsimd_state));



	/* Restore the guest state */
@@ -377,7 +377,7 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code) 
	if (!(read_sysreg(hcr_el2) & HCR_RW))

		write_sysreg(__vcpu_sys_reg(vcpu, FPEXC32_EL2), fpexc32_el2);



	vcpu->arch.fp_state = FP_STATE_GUEST_OWNED;

	*host_data_ptr(fp_owner) = FP_STATE_GUEST_OWNED;



	return true;

}