Re: [PATCH v3 08/10] KVM: arm64: selftests: Add tests for GIC redist/cpuif partially above IPA range

[Ricardo Koller <ricarkol@google.com>]

On Thu, Sep 30, 2021 at 10:51:05AM +0200, Eric Auger wrote:
> Hi Ricardo,
> 
> On 9/28/21 8:48 PM, Ricardo Koller wrote:
> > Add tests for checking that KVM returns the right error when trying to
> > set GICv2 CPU interfaces or GICv3 Redistributors partially above the
> > addressable IPA range. Also tighten the IPA range by replacing
> > KVM_CAP_ARM_VM_IPA_SIZE with the IPA range currently configured for the
> > guest (i.e., the default).
> >
> > The check for the GICv3 redistributor created using the REDIST legacy
> > API is not sufficient as this new test only checks the check done using
> > vcpus already created when setting the base. The next commit will add
> > the missing test which verifies that the KVM check is done at first vcpu
> > run.
> >
> > Signed-off-by: Ricardo Koller <ricarkol@google.com>
> > ---
> >  .../testing/selftests/kvm/aarch64/vgic_init.c | 46 ++++++++++++++-----
> >  1 file changed, 35 insertions(+), 11 deletions(-)
> >
> > diff --git a/tools/testing/selftests/kvm/aarch64/vgic_init.c b/tools/testing/selftests/kvm/aarch64/vgic_init.c
> > index 92f5c6ca6b8b..77a1941e61fa 100644
> > --- a/tools/testing/selftests/kvm/aarch64/vgic_init.c
> > +++ b/tools/testing/selftests/kvm/aarch64/vgic_init.c
> > @@ -31,7 +31,7 @@ struct vm_gic {
> >  	uint32_t gic_dev_type;
> >  };
> >  
> > -static int max_ipa_bits;
> > +static uint64_t max_phys_size;
> >  
> >  /* helper to access a redistributor register */
> >  static int access_v3_redist_reg(int gicv3_fd, int vcpu, int offset,
> > @@ -150,16 +150,21 @@ static void subtest_dist_rdist(struct vm_gic *v)
> >  	TEST_ASSERT(ret && errno == EINVAL, "GIC redist/cpu base not aligned");
> >  
> >  	/* out of range address */
> > -	if (max_ipa_bits) {
> > -		addr = 1ULL << max_ipa_bits;
> > -		ret = _kvm_device_access(v->gic_fd, KVM_DEV_ARM_VGIC_GRP_ADDR,
> > -					 dist.attr, &addr, true);
> > -		TEST_ASSERT(ret && errno == E2BIG, "dist address beyond IPA limit");
> > +	addr = max_phys_size;
> > +	ret = _kvm_device_access(v->gic_fd, KVM_DEV_ARM_VGIC_GRP_ADDR,
> > +				 dist.attr, &addr, true);
> > +	TEST_ASSERT(ret && errno == E2BIG, "dist address beyond IPA limit");
> >  
> > -		ret = _kvm_device_access(v->gic_fd, KVM_DEV_ARM_VGIC_GRP_ADDR,
> > -					 rdist.attr, &addr, true);
> > -		TEST_ASSERT(ret && errno == E2BIG, "redist address beyond IPA limit");
> > -	}
> > +	ret = _kvm_device_access(v->gic_fd, KVM_DEV_ARM_VGIC_GRP_ADDR,
> > +				 rdist.attr, &addr, true);
> > +	TEST_ASSERT(ret && errno == E2BIG, "redist address beyond IPA limit");
> > +
> > +	/* Space for half a rdist (a rdist is: 2 * rdist.alignment). */
> > +	addr = max_phys_size - dist.alignment;
> > +	ret = _kvm_device_access(v->gic_fd, KVM_DEV_ARM_VGIC_GRP_ADDR,
> > +				 rdist.attr, &addr, true);
> > +	TEST_ASSERT(ret && errno == E2BIG,
> > +			"half of the redist is beyond IPA limit");
> >  
> >  	/* set REDIST base address @0x0*/
> >  	addr = 0x00000;
> > @@ -248,7 +253,21 @@ static void subtest_v3_redist_regions(struct vm_gic *v)
> >  	kvm_device_access(v->gic_fd, KVM_DEV_ARM_VGIC_GRP_ADDR,
> >  			  KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION, &addr, true);
> >  
> > -	addr = REDIST_REGION_ATTR_ADDR(1, 1ULL << max_ipa_bits, 0, 2);
> > +	addr = REDIST_REGION_ATTR_ADDR(1, max_phys_size, 0, 2);
> > +	ret = _kvm_device_access(v->gic_fd, KVM_DEV_ARM_VGIC_GRP_ADDR,
> > +				 KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION, &addr, true);
> > +	TEST_ASSERT(ret && errno == E2BIG,
> > +		    "register redist region with base address beyond IPA range");
> > +
> > +	/* The last redist is above the pa range. */
> > +	addr = REDIST_REGION_ATTR_ADDR(1, max_phys_size - 0x10000, 0, 2);
> > +	ret = _kvm_device_access(v->gic_fd, KVM_DEV_ARM_VGIC_GRP_ADDR,
> > +				 KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION, &addr, true);
> > +	TEST_ASSERT(ret && errno == E2BIG,
> > +		    "register redist region with base address beyond IPA range");
> s/base address/top address

ACK

> > +
> > +	/* The last redist is above the pa range. */
> > +	addr = REDIST_REGION_ATTR_ADDR(2, max_phys_size - 0x30000, 0, 2);
> >  	ret = _kvm_device_access(v->gic_fd, KVM_DEV_ARM_VGIC_GRP_ADDR,
> >  				 KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION, &addr, true);
> Why this second check?

Wanted to test having two redists (just a bonus test). This one is
sligthtly more interesting than the previous one, so will just remove
the previous one.

> >  	TEST_ASSERT(ret && errno == E2BIG,
> > @@ -608,8 +627,13 @@ void run_tests(uint32_t gic_dev_type)
> >  int main(int ac, char **av)
> >  {
> >  	int ret;
> > +	int max_ipa_bits, pa_bits;
> >  
> >  	max_ipa_bits = kvm_check_cap(KVM_CAP_ARM_VM_IPA_SIZE);
> > +	pa_bits = vm_guest_mode_params[VM_MODE_DEFAULT].pa_bits;
> > +	TEST_ASSERT(max_ipa_bits && pa_bits <= max_ipa_bits,
> > +		"The default PA range should not be larger than the max.");
> Isn't it already enforced in the test infra instead?
> I see in lib/kvm_util.c
> 
> #ifdef __aarch64__
>         if (vm->pa_bits != 40)
>                 vm->type = KVM_VM_TYPE_ARM_IPA_SIZE(vm->pa_bits);
> #endif

You are right, and this is a weird place to make that check.

> 
> vm_open()
> > +	max_phys_size = 1ULL << pa_bits;
> >  
> >  	ret = test_kvm_device(KVM_DEV_TYPE_ARM_VGIC_V3);
> >  	if (!ret) {
> Eric
>

Thanks,
Ricardo