Commit 1b8570be authored by Marc Zyngier's avatar Marc Zyngier
Browse files

KVM: arm64: Compute FGT masks from KVM's own FGT tables 



In the process of decoupling KVM's view of the FGT bits from the
wider architectural state, use KVM's own FGT tables to build
a synthetic view of what is actually known.

This allows for some checking along the way.

Reviewed-by: default avatarJoey Gouly <joey.gouly@arm.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 5329358c

arch/arm64/include/asm/kvm_host.h

+14 −0
Original line number Diff line number Diff line
@@ -607,6 +607,20 @@ struct kvm_sysreg_masks { 
	} mask[NR_SYS_REGS - __SANITISED_REG_START__];

};



struct fgt_masks {

	const char	*str;

	u64		mask;

	u64		nmask;

	u64		res0;

};



extern struct fgt_masks hfgrtr_masks;

extern struct fgt_masks hfgwtr_masks;

extern struct fgt_masks hfgitr_masks;

extern struct fgt_masks hdfgrtr_masks;

extern struct fgt_masks hdfgwtr_masks;

extern struct fgt_masks hafgrtr_masks;



struct kvm_cpu_context {

	struct user_pt_regs regs;	/* sp = sp_el0 */

arch/arm64/kvm/emulate-nested.c

+106 −0
Original line number Diff line number Diff line
@@ -2033,6 +2033,105 @@ static u32 encoding_next(u32 encoding) 
	return sys_reg(op0 + 1, 0, 0, 0, 0);

}



#define FGT_MASKS(__n, __m)						\

	struct fgt_masks __n = { .str = #__m, .res0 = __m, }



FGT_MASKS(hfgrtr_masks, HFGRTR_EL2_RES0);

FGT_MASKS(hfgwtr_masks, HFGWTR_EL2_RES0);

FGT_MASKS(hfgitr_masks, HFGITR_EL2_RES0);

FGT_MASKS(hdfgrtr_masks, HDFGRTR_EL2_RES0);

FGT_MASKS(hdfgwtr_masks, HDFGWTR_EL2_RES0);

FGT_MASKS(hafgrtr_masks, HAFGRTR_EL2_RES0);



static __init bool aggregate_fgt(union trap_config tc)

{

	struct fgt_masks *rmasks, *wmasks;



	switch (tc.fgt) {

	case HFGRTR_GROUP:

		rmasks = &hfgrtr_masks;

		wmasks = &hfgwtr_masks;

		break;

	case HDFGRTR_GROUP:

		rmasks = &hdfgrtr_masks;

		wmasks = &hdfgwtr_masks;

		break;

	case HAFGRTR_GROUP:

		rmasks = &hafgrtr_masks;

		wmasks = NULL;

		break;

	case HFGITR_GROUP:

		rmasks = &hfgitr_masks;

		wmasks = NULL;

		break;

	}



	/*

	 * A bit can be reserved in either the R or W register, but

	 * not both.

	 */

	if ((BIT(tc.bit) & rmasks->res0) &&

	    (!wmasks || (BIT(tc.bit) & wmasks->res0)))

		return false;



	if (tc.pol)

		rmasks->mask |= BIT(tc.bit) & ~rmasks->res0;

	else

		rmasks->nmask |= BIT(tc.bit) & ~rmasks->res0;



	if (wmasks) {

		if (tc.pol)

			wmasks->mask |= BIT(tc.bit) & ~wmasks->res0;

		else

			wmasks->nmask |= BIT(tc.bit) & ~wmasks->res0;

	}



	return true;

}



static __init int check_fgt_masks(struct fgt_masks *masks)

{

	unsigned long duplicate = masks->mask & masks->nmask;

	u64 res0 = masks->res0;

	int ret = 0;



	if (duplicate) {

		int i;



		for_each_set_bit(i, &duplicate, 64) {

			kvm_err("%s[%d] bit has both polarities\n",

				masks->str, i);

		}



		ret = -EINVAL;

	}



	masks->res0 = ~(masks->mask | masks->nmask);

	if (masks->res0 != res0)

		kvm_info("Implicit %s = %016llx, expecting %016llx\n",

			 masks->str, masks->res0, res0);



	return ret;

}



static __init int check_all_fgt_masks(int ret)

{

	static struct fgt_masks * const masks[] __initconst = {

		&hfgrtr_masks,

		&hfgwtr_masks,

		&hfgitr_masks,

		&hdfgrtr_masks,

		&hdfgwtr_masks,

		&hafgrtr_masks,

	};

	int err = 0;



	for (int i = 0; i < ARRAY_SIZE(masks); i++)

		err |= check_fgt_masks(masks[i]);



	return ret ?: err;

}



int __init populate_nv_trap_config(void)

{

	int ret = 0;
@@ -2097,8 +2196,15 @@ int __init populate_nv_trap_config(void) 
			ret = xa_err(prev);

			print_nv_trap_error(fgt, "Failed FGT insertion", ret);

		}



		if (!aggregate_fgt(tc)) {

			ret = -EINVAL;

			print_nv_trap_error(fgt, "FGT bit is reserved", ret);

		}

	}



	ret = check_all_fgt_masks(ret);



	kvm_info("nv: %ld fine grained trap handlers\n",

		 ARRAY_SIZE(encoding_to_fgt));