Commit 831bf664 authored by Sasha Levin's avatar Sasha Levin Committed by Avi Kivity
Browse files

KVM: Refactor and simplify kvm_dev_ioctl_get_supported_cpuid 



This patch cleans and simplifies kvm_dev_ioctl_get_supported_cpuid by using a table
instead of duplicating code as Avi suggested.

This patch also fixes a bug where kvm_dev_ioctl_get_supported_cpuid would return
-E2BIG when amount of entries passed was just right.

Signed-off-by: default avatarSasha Levin <levinsasha928@gmail.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent fb215366

arch/x86/kvm/cpuid.c

+63 −50
Original line number Diff line number Diff line
@@ -183,9 +183,10 @@ static bool supported_xcr0_bit(unsigned bit) 


#define F(x) bit(X86_FEATURE_##x)



static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,

static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,

			 u32 index, int *nent, int maxnent)

{

	int r;

	unsigned f_nx = is_efer_nx() ? F(NX) : 0;

#ifdef CONFIG_X86_64

	unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL)
@@ -246,6 +247,12 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, 


	/* all calls to cpuid_count() should be made on the same cpu */

	get_cpu();



	r = -E2BIG;



	if (*nent >= maxnent)

		goto out;



	do_cpuid_1_ent(entry, function, index);

	++*nent;
@@ -271,7 +278,10 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, 


		entry->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;

		entry->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;

		for (t = 1; t < times && *nent < maxnent; ++t) {

		for (t = 1; t < times; ++t) {

			if (*nent >= maxnent)

				goto out;



			do_cpuid_1_ent(&entry[t], function, 0);

			entry[t].flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;

			++*nent;
@@ -284,7 +294,10 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, 


		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;

		/* read more entries until cache_type is zero */

		for (i = 1; *nent < maxnent; ++i) {

		for (i = 1; ; ++i) {

			if (*nent >= maxnent)

				goto out;



			cache_type = entry[i - 1].eax & 0x1f;

			if (!cache_type)

				break;
@@ -316,7 +329,10 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, 


		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;

		/* read more entries until level_type is zero */

		for (i = 1; *nent < maxnent; ++i) {

		for (i = 1; ; ++i) {

			if (*nent >= maxnent)

				goto out;



			level_type = entry[i - 1].ecx & 0xff00;

			if (!level_type)

				break;
@@ -331,7 +347,10 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, 
		int idx, i;



		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;

		for (idx = 1, i = 1; *nent < maxnent && idx < 64; ++idx) {

		for (idx = 1, i = 1; idx < 64; ++idx) {

			if (*nent >= maxnent)

				goto out;



			do_cpuid_1_ent(&entry[i], function, idx);

			if (entry[i].eax == 0 || !supported_xcr0_bit(idx))

				continue;
@@ -416,17 +435,41 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, 


	kvm_x86_ops->set_supported_cpuid(function, entry);



	r = 0;



out:

	put_cpu();



	return r;

}



#undef F



struct kvm_cpuid_param {

	u32 func;

	u32 idx;

	bool has_leaf_count;

	bool (*qualifier)(struct kvm_cpuid_param *param);

};



static bool is_centaur_cpu(struct kvm_cpuid_param *param)

{

	return boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR;

}



int kvm_dev_ioctl_get_supported_cpuid(struct kvm_cpuid2 *cpuid,

				      struct kvm_cpuid_entry2 __user *entries)

{

	struct kvm_cpuid_entry2 *cpuid_entries;

	int limit, nent = 0, r = -E2BIG;

	int limit, nent = 0, r = -E2BIG, i;

	u32 func;

	static struct kvm_cpuid_param param[] = {

		{ .func = 0, .has_leaf_count = true },

		{ .func = 0x80000000, .has_leaf_count = true },

		{ .func = 0xC0000000, .qualifier = is_centaur_cpu, .has_leaf_count = true },

		{ .func = KVM_CPUID_SIGNATURE },

		{ .func = KVM_CPUID_FEATURES },

	};



	if (cpuid->nent < 1)

		goto out;
@@ -437,61 +480,31 @@ int kvm_dev_ioctl_get_supported_cpuid(struct kvm_cpuid2 *cpuid, 
	if (!cpuid_entries)

		goto out;



	do_cpuid_ent(&cpuid_entries[0], 0, 0, &nent, cpuid->nent);

	limit = cpuid_entries[0].eax;

	for (func = 1; func <= limit && nent < cpuid->nent; ++func)

		do_cpuid_ent(&cpuid_entries[nent], func, 0,

			     &nent, cpuid->nent);

	r = -E2BIG;

	if (nent >= cpuid->nent)

		goto out_free;



	do_cpuid_ent(&cpuid_entries[nent], 0x80000000, 0, &nent, cpuid->nent);

	limit = cpuid_entries[nent - 1].eax;

	for (func = 0x80000001; func <= limit && nent < cpuid->nent; ++func)

		do_cpuid_ent(&cpuid_entries[nent], func, 0,

			     &nent, cpuid->nent);





	r = 0;

	for (i = 0; i < ARRAY_SIZE(param); i++) {

		struct kvm_cpuid_param *ent = &param[i];



	r = -E2BIG;

	if (nent >= cpuid->nent)

		goto out_free;

		if (ent->qualifier && !ent->qualifier(ent))

			continue;



	/* Add support for Centaur's CPUID instruction. */

	if (boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR) {

		do_cpuid_ent(&cpuid_entries[nent], 0xC0000000, 0,

		r = do_cpuid_ent(&cpuid_entries[nent], ent->func, ent->idx,

				&nent, cpuid->nent);



		r = -E2BIG;

		if (nent >= cpuid->nent)

		if (r)

			goto out_free;



		if (!ent->has_leaf_count)

			continue;



		limit = cpuid_entries[nent - 1].eax;

		for (func = 0xC0000001;

			func <= limit && nent < cpuid->nent; ++func)

			do_cpuid_ent(&cpuid_entries[nent], func, 0,

		for (func = ent->func + 1; func <= limit && nent < cpuid->nent && r == 0; ++func)

			r = do_cpuid_ent(&cpuid_entries[nent], func, ent->idx,

				     &nent, cpuid->nent);



		r = -E2BIG;

		if (nent >= cpuid->nent)

		if (r)

			goto out_free;

	}



	do_cpuid_ent(&cpuid_entries[nent], KVM_CPUID_SIGNATURE, 0, &nent,

		     cpuid->nent);



	r = -E2BIG;

	if (nent >= cpuid->nent)

		goto out_free;



	do_cpuid_ent(&cpuid_entries[nent], KVM_CPUID_FEATURES, 0, &nent,

		     cpuid->nent);



	r = -E2BIG;

	if (nent >= cpuid->nent)

		goto out_free;



	r = -EFAULT;

	if (copy_to_user(entries, cpuid_entries,

			 nent * sizeof(struct kvm_cpuid_entry2)))

CRA Git | Maintained and supported by SUSTech CRA and CCSE