Re: [PATCH v3 07/10] selftests: kvm: s390: Add uc_map_unmap VM test case

[Janosch Frank <frankja@linux.ibm.com>]

On 7/30/24 9:24 AM, Christoph Schlameuss wrote:
> Add a test case verifying basic running and interaction of ucontrol VMs.
> Fill the segment and page tables for allocated memory and map memory on
> first access.
> 
> * uc_map_unmap
>    Store and load data to mapped and unmapped memory and use pic segment
>    translation handling to map memory on access.
> 
> Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
> ---
>   .../selftests/kvm/s390x/ucontrol_test.c       | 165 +++++++++++++++++-
>   1 file changed, 164 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/kvm/s390x/ucontrol_test.c b/tools/testing/selftests/kvm/s390x/ucontrol_test.c
> index 817b1e08559c..b7f760f980fd 100644
> --- a/tools/testing/selftests/kvm/s390x/ucontrol_test.c
> +++ b/tools/testing/selftests/kvm/s390x/ucontrol_test.c
> @@ -16,7 +16,13 @@
>   #include <linux/capability.h>
>   #include <linux/sizes.h>
>   
> +#define UC_PIC_SEGMENT_TRANSLATION 0x10

That's a bit clearer and used by KVM:
#define PGM_SEGMENT_TRANSLATION		0x10

> +
>   #define VM_MEM_SIZE (4 * SZ_1M)
> +#define VM_MEM_EXT_SIZE (2 * SZ_1M)
> +#define VM_MEM_MAX (VM_MEM_SIZE + VM_MEM_EXT_SIZE)
> +

[...]

> +	self->pgd = self->base_gpa + SZ_1M; /* set PASCE addr */

Please put the comments on the line above

> +	phd = gpa2hva(self, self->pgd);
> +	memset(phd, 0xff, PAGES_PER_SEGMENT * PAGE_SIZE);
> +
> +	for (si = 0; si < ((VM_MEM_SIZE + VM_MEM_EXT_SIZE) / SZ_1M); si++) {
> +		/* create ste */
> +		phd[si] = (self->pgd
> +			+ (PAGES_PER_SEGMENT * PAGE_SIZE
> +				* ((VM_MEM_SIZE + VM_MEM_EXT_SIZE) / SZ_1M))
> +			+ (PAGES_PER_SEGMENT * PAGE_SIZE * si)) & ~0x7fful;
> +		se_addr = gpa2hva(self, phd[si]);
> +		memset(se_addr, 0xff, PAGES_PER_SEGMENT * PAGE_SIZE);
> +		for (pi = 0; pi < (SZ_1M / PAGE_SIZE); pi++) {
> +			/* create pte */
> +			((u64 *)se_addr)[pi] = (self->base_gpa
> +				+ (si * SZ_1M) + (pi * PAGE_SIZE)) & ~0xffful;
> +		}
> +	}
> +	pr_debug("segment table entry %p (0x%lx) --> %p\n",
> +		 phd, phd[0], gpa2hva(self, (phd[0] & ~0x7fful)));
> +	print_hex_bytes("st", (u64)phd, 64);
> +	print_hex_bytes("pt", (u64)gpa2hva(self, phd[0]), 128);
> +	print_hex_bytes("pt+", (u64)
> +			gpa2hva(self, phd[0] + (PAGES_PER_SEGMENT * PAGE_SIZE
> +			* ((VM_MEM_SIZE + VM_MEM_EXT_SIZE) / SZ_1M)) - 0x64), 128);
> +
> +	sync_regs->crs[1] = self->pgd | 0x3;	/* PASCE TT=00 for segment table */

Same here

> +	run->kvm_dirty_regs |= KVM_SYNC_CRS;
> +}
> +
> +static void uc_handle_exit_ucontrol(FIXTURE_DATA(uc_kvm) * self)
> +{
> +	struct kvm_run *run = self->run;
> +
> +	TEST_ASSERT_EQ(KVM_EXIT_S390_UCONTROL, run->exit_reason);
> +	switch (run->s390_ucontrol.pgm_code) {
> +	case UC_PIC_SEGMENT_TRANSLATION:
> +		pr_info("ucontrol pic segment translation 0x%llx\n",
> +			run->s390_ucontrol.trans_exc_code);
> +		/* map / make additional memory available */
> +		struct kvm_s390_ucas_mapping map2 = {
> +			.user_addr = (u64)gpa2hva(self, run->s390_ucontrol.trans_exc_code),
> +			.vcpu_addr = run->s390_ucontrol.trans_exc_code,
> +			.length = VM_MEM_EXT_SIZE,
> +		};
> +		pr_info("ucas map %p %p 0x%llx\n",
> +			(void *)map2.user_addr, (void *)map2.vcpu_addr, map2.length);
> +		TEST_ASSERT_EQ(0, ioctl(self->vcpu_fd, KVM_S390_UCAS_MAP, &map2));
> +		break;
> +	default:
> +		TEST_FAIL("UNEXPECTED PGM CODE %d", run->s390_ucontrol.pgm_code);
> +	}
> +}
> +
>   /* verify SIEIC exit
>    * * reset stop requests
>    * * fail on codes not expected in the test cases
> @@ -245,7 +338,11 @@ static bool uc_handle_sieic(FIXTURE_DATA(uc_kvm) * self)
>   		break;
>   	case ICPT_INST:
>   		/* end execution in caller on intercepted instruction */
> +		pr_info("sie instruction interception\n");

That should have been part of an earlier patch?

>   		return false;
> +	case ICPT_OPEREXC:
> +		/* operation exception */
> +		TEST_FAIL("sie exception on %.4x%.8x", sie_block->ipa, sie_block->ipb);
>   	default:
>   		TEST_FAIL("UNEXPECTED SIEIC CODE %d", run->s390_sieic.icptcode);
>   	}
> @@ -258,6 +355,11 @@ static bool uc_handle_exit(FIXTURE_DATA(uc_kvm) * self)
>   	struct kvm_run *run = self->run;
>   
>   	switch (run->exit_reason) {
> +	case KVM_EXIT_S390_UCONTROL:
> +		/* check program interruption code */
> +		/* handle page fault --> ucas map */

Multi-line comments do exist

> +		uc_handle_exit_ucontrol(self);
> +		break;
>   	case KVM_EXIT_S390_SIEIC:
>   		return uc_handle_sieic(self);
>   	default:
> @@ -289,6 +391,67 @@ static void uc_assert_diag44(FIXTURE_DATA(uc_kvm) * self)
>   	TEST_ASSERT_EQ(0x440000, sie_block->ipb);
>   }
>   
> +TEST_F(uc_kvm, uc_map_unmap)
> +{
> +	struct kvm_sync_regs *sync_regs = &self->run->s.regs;
> +	struct kvm_run *run = self->run;
> +	int rc;
> +
> +	init_st_pt(self);
> +
> +	/* copy test_mem_asm to code_hva / code_gpa */
> +	TH_LOG("copy code %p to vm mapped memory %p / %p",
> +	       &test_mem_asm, (void *)self->code_hva, (void *)self->code_gpa);
> +	memcpy((void *)self->code_hva, &test_mem_asm, PAGE_SIZE);
> +
> +	run->psw_mask = 0x0400000180000000ULL;  /* DAT enabled + 64 bit mode */
> +	run->psw_addr = self->code_gpa;


Please put the comments on the line above

> +
> +	/* set register content for test_mem_asm to access not mapped memory*/
> +	sync_regs->gprs[1] = 0x55;
> +	sync_regs->gprs[5] = self->base_gpa;
> +	sync_regs->gprs[6] = VM_MEM_SIZE;
> +	run->kvm_dirty_regs |= KVM_SYNC_GPRS;
> +
> +	/* run and expect to fail witch ucontrol pic segment translation */
> +	ASSERT_EQ(0, uc_run_once(self));
> +	ASSERT_EQ(1, sync_regs->gprs[0]);
> +	ASSERT_EQ(KVM_EXIT_S390_UCONTROL, run->exit_reason);
> +
> +	ASSERT_EQ(UC_PIC_SEGMENT_TRANSLATION, run->s390_ucontrol.pgm_code);
> +	ASSERT_EQ(self->base_gpa + VM_MEM_SIZE, run->s390_ucontrol.trans_exc_code);
> +	/* map / make additional memory available */
> +	struct kvm_s390_ucas_mapping map2 = {
> +		.user_addr = (u64)gpa2hva(self, self->base_gpa + VM_MEM_SIZE),
> +		.vcpu_addr = self->base_gpa + VM_MEM_SIZE,
> +		.length = VM_MEM_EXT_SIZE,
> +	};
> +	TH_LOG("ucas map %p %p 0x%llx",
> +	       (void *)map2.user_addr, (void *)map2.vcpu_addr, map2.length);
> +	rc = ioctl(self->vcpu_fd, KVM_S390_UCAS_MAP, &map2);
> +	ASSERT_EQ(0, rc)
> +		TH_LOG("ucas map result %d not expected, %s", rc, strerror(errno));
> +	ASSERT_EQ(0, uc_run_once(self));
> +	ASSERT_EQ(false, uc_handle_exit(self));
> +	uc_assert_diag44(self);
> +
> +	/* assert registers and memory are in expected state */
> +	ASSERT_EQ(2, sync_regs->gprs[0]);
> +	ASSERT_EQ(0x55, sync_regs->gprs[1]);
> +	ASSERT_EQ(0x55, *(u32 *)gpa2hva(self, self->base_gpa + VM_MEM_SIZE));
> +
> +	/* unmap and run loop again */
> +	TH_LOG("ucas unmap %p %p 0x%llx",
> +	       (void *)map2.user_addr, (void *)map2.vcpu_addr, map2.length);
> +	rc = ioctl(self->vcpu_fd, KVM_S390_UCAS_UNMAP, &map2);
> +	ASSERT_EQ(0, rc)
> +		TH_LOG("ucas map result %d not expected, %s", rc, strerror(errno));
> +	ASSERT_EQ(0, uc_run_once(self));
> +	ASSERT_EQ(3, sync_regs->gprs[0]);
> +	ASSERT_EQ(KVM_EXIT_S390_UCONTROL, run->exit_reason);
> +	ASSERT_EQ(true, uc_handle_exit(self));
> +}
> +
>   TEST_F(uc_kvm, uc_gprs)
>   {
>   	struct kvm_sync_regs *sync_regs = &self->run->s.regs;