Re: [kvm-unit-tests PATCH v3 07/10] arm64: selftest: update test for running at EL2

[Joey Gouly <joey.gouly@arm.com>]

On Tue, Dec 02, 2025 at 10:16:42AM +0100, Eric Auger wrote:
> 
> 
> On 9/25/25 4:19 PM, Joey Gouly wrote:
> > From: Alexandru Elisei <alexandru.elisei@arm.com>
> >
> > Remove some hard-coded assumptions that this test is running at EL1.
> >
> > Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
> > Signed-off-by: Joey Gouly <joey.gouly@arm.com>
> > ---
> >  arm/selftest.c | 18 +++++++++++++-----
> >  1 file changed, 13 insertions(+), 5 deletions(-)
> >
> > diff --git a/arm/selftest.c b/arm/selftest.c
> > index 1553ed8e..01691389 100644
> > --- a/arm/selftest.c
> > +++ b/arm/selftest.c
> > @@ -232,6 +232,7 @@ static void user_psci_system_off(struct pt_regs *regs)
> >  	__user_psci_system_off();
> >  }
> >  #elif defined(__aarch64__)
> > +static unsigned long expected_level;
> >  
> >  /*
> >   * Capture the current register state and execute an instruction
> > @@ -276,8 +277,7 @@ static bool check_regs(struct pt_regs *regs)
> >  {
> >  	unsigned i;
> >  
> > -	/* exception handlers should always run in EL1 */
> > -	if (current_level() != CurrentEL_EL1)
> > +	if (current_level() != expected_level)
> >  		return false;
> >  
> >  	for (i = 0; i < ARRAY_SIZE(regs->regs); ++i) {
> > @@ -301,7 +301,11 @@ static enum vector check_vector_prep(void)
> >  		return EL0_SYNC_64;
> >  
> >  	asm volatile("mrs %0, daif" : "=r" (daif) ::);
> > -	expected_regs.pstate = daif | PSR_MODE_EL1h;
> > +	expected_regs.pstate = daif;
> > +	if (current_level() == CurrentEL_EL1)
> > +		expected_regs.pstate |= PSR_MODE_EL1h;
> > +	else
> > +		expected_regs.pstate |= PSR_MODE_EL2h;
> >  	return EL1H_SYNC;
> >  }
> >  
> > @@ -317,8 +321,8 @@ static bool check_und(void)
> >  
> >  	install_exception_handler(v, ESR_EL1_EC_UNKNOWN, unknown_handler);
> >  
> > -	/* try to read an el2 sysreg from el0/1 */
> > -	test_exception("", "mrs x0, sctlr_el2", "", "x0");
> > +	/* try to read an el3 sysreg from el0/1/2 */
> > +	test_exception("", "mrs x0, sctlr_el3", "", "x0");
> >  
> >  	install_exception_handler(v, ESR_EL1_EC_UNKNOWN, NULL);
> >  
> > @@ -429,6 +433,10 @@ int main(int argc, char **argv)
> >  	if (argc < 2)
> >  		report_abort("no test specified");
> >  
> > +#if defined(__aarch64__)
> > +	expected_level = current_level();
> nit I would directly use current_level() in the calling function,
> check_regs() to avoid that #ifdef

I can't move it into check_regs() because that's what's checking the exception
level of the handler is what the expected_level is.

Something like this (untested) would work:

diff --git a/arm/selftest.c b/arm/selftest.c
index 01691389..f173bc99 100644
--- a/arm/selftest.c
+++ b/arm/selftest.c
@@ -215,6 +215,7 @@ static void pabt_handler(struct pt_regs *regs)
 
 static bool check_pabt(void)
 {
+       expected_level = current_level();
        install_exception_handler(EXCPTN_PABT, pabt_handler);
 
        test_exception("ldr     r9, =check_pabt_invalid_paddr\n"
@@ -318,6 +319,7 @@ static void unknown_handler(struct pt_regs *regs, unsigned int esr __unused)
 static bool check_und(void)
 {
        enum vector v = check_vector_prep();
+       expected_level = current_level();
 
        install_exception_handler(v, ESR_EL1_EC_UNKNOWN, unknown_handler);
 
@@ -340,6 +342,7 @@ static void svc_handler(struct pt_regs *regs, unsigned int esr)
 static bool check_svc(void)
 {
        enum vector v = check_vector_prep();
+       expected_level = current_level();
 
        install_exception_handler(v, ESR_EL1_EC_SVC64, svc_handler);
 
@@ -433,10 +436,6 @@ int main(int argc, char **argv)
        if (argc < 2)
                report_abort("no test specified");
 
-#if defined(__aarch64__)
-       expected_level = current_level();
-#endif
-
        report_prefix_push(argv[1]);
 
        if (strcmp(argv[1], "setup") == 0) {

Is that preferable than an #ifdef?

Thanks,
Joey
> 
> Eric
> > +#endif
> > +
> >  	report_prefix_push(argv[1]);
> >  
> >  	if (strcmp(argv[1], "setup") == 0) {
>