Commit 4d2bd143 authored by David Matlack's avatar David Matlack Committed by Paolo Bonzini
Browse files

KVM: selftests: Add helpers to read kvm_{intel,amd} boolean module parameters 



Add helper functions for reading the value of kvm_intel and kvm_amd
boolean module parameters. Use the kvm_intel variant in
vm_is_unrestricted_guest() to simplify the check for
kvm_intel.unrestricted_guest.

No functional change intended.

Signed-off-by: default avatarDavid Matlack <dmatlack@google.com>
Message-Id: <20220929181207.2281449-3-dmatlack@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 62ece2c5

tools/testing/selftests/kvm/include/kvm_util_base.h

+4 −0
Original line number Diff line number Diff line
@@ -175,6 +175,10 @@ extern const struct vm_guest_mode_params vm_guest_mode_params[]; 


int open_path_or_exit(const char *path, int flags);

int open_kvm_dev_path_or_exit(void);



bool get_kvm_intel_param_bool(const char *param);

bool get_kvm_amd_param_bool(const char *param);



unsigned int kvm_check_cap(long cap);



static inline bool kvm_has_cap(long cap)

tools/testing/selftests/kvm/lib/kvm_util.c

+39 −0
Original line number Diff line number Diff line
@@ -50,6 +50,45 @@ int open_kvm_dev_path_or_exit(void) 
	return _open_kvm_dev_path_or_exit(O_RDONLY);

}



static bool get_module_param_bool(const char *module_name, const char *param)

{

	const int path_size = 128;

	char path[path_size];

	char value;

	ssize_t r;

	int fd;



	r = snprintf(path, path_size, "/sys/module/%s/parameters/%s",

		     module_name, param);

	TEST_ASSERT(r < path_size,

		    "Failed to construct sysfs path in %d bytes.", path_size);



	fd = open_path_or_exit(path, O_RDONLY);



	r = read(fd, &value, 1);

	TEST_ASSERT(r == 1, "read(%s) failed", path);



	r = close(fd);

	TEST_ASSERT(!r, "close(%s) failed", path);



	if (value == 'Y')

		return true;

	else if (value == 'N')

		return false;



	TEST_FAIL("Unrecognized value '%c' for boolean module param", value);

}



bool get_kvm_intel_param_bool(const char *param)

{

	return get_module_param_bool("kvm_intel", param);

}



bool get_kvm_amd_param_bool(const char *param)

{

	return get_module_param_bool("kvm_amd", param);

}



/*

 * Capability

 *

tools/testing/selftests/kvm/lib/x86_64/processor.c

+1 −12
Original line number Diff line number Diff line
@@ -1294,20 +1294,9 @@ unsigned long vm_compute_max_gfn(struct kvm_vm *vm) 
/* Returns true if kvm_intel was loaded with unrestricted_guest=1. */

bool vm_is_unrestricted_guest(struct kvm_vm *vm)

{

	char val = 'N';

	size_t count;

	FILE *f;



	/* Ensure that a KVM vendor-specific module is loaded. */

	if (vm == NULL)

		close(open_kvm_dev_path_or_exit());



	f = fopen("/sys/module/kvm_intel/parameters/unrestricted_guest", "r");

	if (f) {

		count = fread(&val, sizeof(char), 1, f);

		TEST_ASSERT(count == 1, "Unable to read from param file.");

		fclose(f);

	}



	return val == 'Y';

	return get_kvm_intel_param_bool("unrestricted_guest");

}