[PATCH v6 0/4] x86/tests: Add tests for AMD SEV-ES #VC handling

[PATCH v6 0/4] x86/tests: Add tests for AMD SEV-ES #VC handling

[Vasant Karasulli]

Hi All,

   This is the version 6 of the patch written to add tests for
   AMD SEV-ES #VC handling. This version attempts to
   address review comments to the previous version of the patch in
   https://lore.kernel.org/kvm/20220208162623.18368-1-vkarasulli@suse.de/.

   Changes in this version:
   1. The patch in the previous version is split into 4 parts.
   2. Constants in function sev_es_nae_mmio are replaced by macros.

Thanks,
Vasant

Vasant Karasulli (4):
  x86/tests: Add Kconfig options for testing AMD SEV related features.
  x86/tests: Add KUnit based tests to validate Linux's VC handling for
    instructions cpuid and wbinvd. These tests: 1. install a kretprobe
    on the #VC handler (sev_es_ghcb_hv_call, to    access GHCB
    before/after the resulting VMGEXIT). 2. trigger an NAE by executing
    either cpuid or wbinvd. 3. check that the kretprobe was hit with the
    right exit_code available    in GHCB.
  x86/tests: Add KUnit based tests to validate Linux's VC handling for
      instructions accessing registers such as MSR and DR7. These tests:
        1. install a kretprobe on the #VC handler (sev_es_ghcb_hv_call,
    to        access GHCB before/after the resulting VMGEXIT).     2.
    trigger an NAE by accessing either MSR or DR7.     3. check that the
    kretprobe was hit with the right exit_code available        in GHCB.
  x86/tests: Add KUnit based tests to validate Linux's VC handling for
          IO instructions. These tests:         1. install a kretprobe
    on the #VC handler (sev_es_ghcb_hv_call, to            access GHCB
    before/after the resulting VMGEXIT).         2. trigger an NAE by
    issuing an IO instruction.         3. check that the kretprobe was
    hit with the right exit_code available            in GHCB.

 arch/x86/Kbuild              |   2 +
 arch/x86/Kconfig.debug       |  16 ++++
 arch/x86/kernel/Makefile     |   7 ++
 arch/x86/tests/Makefile      |   3 +
 arch/x86/tests/sev-test-vc.c | 155 +++++++++++++++++++++++++++++++++++
 5 files changed, 183 insertions(+)
 create mode 100644 arch/x86/tests/Makefile
 create mode 100644 arch/x86/tests/sev-test-vc.c


base-commit: 09688c0166e76ce2fb85e86b9d99be8b0084cdf9
prerequisite-patch-id: b74bc39d7ca69ad86b5f9090047c44ab039f4622
prerequisite-patch-id: a53a291b59b4ceaffa25a9a08dfa08b5a78a01b9
--
2.32.0

[PATCH v6 1/4] x86/tests: Add tests for AMD SEV-ES #VC handling Add Kconfig options for testing AMD SEV related features.

[Vasant Karasulli]

Signed-off-by: Vasant Karasulli <vkarasulli@suse.de>
---
 arch/x86/Kbuild          |  2 ++
 arch/x86/Kconfig.debug   | 16 ++++++++++++++++
 arch/x86/kernel/Makefile |  7 +++++++
 arch/x86/tests/Makefile  |  1 +
 4 files changed, 26 insertions(+)
 create mode 100644 arch/x86/tests/Makefile

diff --git a/arch/x86/Kbuild b/arch/x86/Kbuild
index f384cb1a4f7a..90470c76866a 100644
--- a/arch/x86/Kbuild
+++ b/arch/x86/Kbuild
@@ -26,5 +26,7 @@ obj-y += net/

 obj-$(CONFIG_KEXEC_FILE) += purgatory/

+obj-y += tests/
+
 # for cleaning
 subdir- += boot tools
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index d3a6f74a94bd..e4f61af66816 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -279,3 +279,19 @@ endchoice
 config FRAME_POINTER
 	depends on !UNWINDER_ORC && !UNWINDER_GUESS
 	bool
+
+config X86_TESTS
+	bool "Tests for x86"
+	help
+	    This enables building the tests under arch/x86/tests.
+
+if X86_TESTS
+config AMD_SEV_TEST_VC
+	bool "Test for AMD SEV VC exception handling"
+	depends on AMD_MEM_ENCRYPT
+	select FUNCTION_TRACER
+	select KPROBES
+	select KUNIT
+	help
+	  Enable KUnit-based testing for AMD SEV #VC exception handling.
+endif # X86_TESTS
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 6aef9ee28a39..69472a576909 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -24,6 +24,13 @@ CFLAGS_REMOVE_sev.o = -pg
 CFLAGS_REMOVE_cc_platform.o = -pg
 endif

+# AMD_SEV_TEST_VC registers a kprobe by function name. IPA-SRA creates
+# function copies and renames them to have an .isra suffix, which breaks kprobes'
+# lookup. Build with -fno-ipa-sra for the test.
+ifdef CONFIG_AMD_SEV_TEST_VC
+CFLAGS_sev.o	+= -fno-ipa-sra
+endif
+
 KASAN_SANITIZE_head$(BITS).o				:= n
 KASAN_SANITIZE_dumpstack.o				:= n
 KASAN_SANITIZE_dumpstack_$(BITS).o			:= n
diff --git a/arch/x86/tests/Makefile b/arch/x86/tests/Makefile
new file mode 100644
index 000000000000..f66554cd5c45
--- /dev/null
+++ b/arch/x86/tests/Makefile
@@ -0,0 +1 @@
+# SPDX-License-Identifier: GPL-2.0
--
2.32.0

[PATCH v6 2/4] x86/tests: Add tests for AMD SEV-ES #VC handling Add KUnit based tests to validate Linux's VC handling for instructions cpuid and wbinvd. These tests: 1. install a kretprobe on the #VC handler (sev_es_ghcb_hv_call, to access GHCB before/after the resulting VMGEXIT). 2. trigger an NAE by executing either cpuid or wbinvd. 3. check that the kretprobe was hit with the right exit_code available in GHCB.

[Vasant Karasulli]

Signed-off-by: Vasant Karasulli <vkarasulli@suse.de>
---
 arch/x86/tests/Makefile      |   2 +
 arch/x86/tests/sev-test-vc.c | 114 +++++++++++++++++++++++++++++++++++
 2 files changed, 116 insertions(+)
 create mode 100644 arch/x86/tests/sev-test-vc.c

diff --git a/arch/x86/tests/Makefile b/arch/x86/tests/Makefile
index f66554cd5c45..4beca64bd2aa 100644
--- a/arch/x86/tests/Makefile
+++ b/arch/x86/tests/Makefile
@@ -1 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_AMD_SEV_TEST_VC)	+= sev-test-vc.o
diff --git a/arch/x86/tests/sev-test-vc.c b/arch/x86/tests/sev-test-vc.c
new file mode 100644
index 000000000000..9d415b9708dc
--- /dev/null
+++ b/arch/x86/tests/sev-test-vc.c
@@ -0,0 +1,114 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2021 SUSE
+ *
+ * Author: Varad Gautam <varad.gautam@suse.com>
+ */
+
+#include <asm/cpufeature.h>
+#include <asm/sev-common.h>
+#include <asm/svm.h>
+#include <kunit/test.h>
+#include <linux/kprobes.h>
+
+static struct kretprobe hv_call_krp;
+
+static int hv_call_krp_entry(struct kretprobe_instance *krpi,
+			     struct pt_regs *regs)
+{
+	unsigned long ghcb_vaddr = regs_get_kernel_argument(regs, 0);
+	*((unsigned long *) krpi->data) = ghcb_vaddr;
+
+	return 0;
+}
+
+static int hv_call_krp_ret(struct kretprobe_instance *krpi,
+			   struct pt_regs *regs)
+{
+	unsigned long ghcb_vaddr = *((unsigned long *) krpi->data);
+	struct ghcb *ghcb = (struct ghcb *) ghcb_vaddr;
+	struct kunit *test = current->kunit_test;
+
+	if (test && strstr(test->name, "sev_es_") && test->priv)
+		*((u64 *)test->priv) = ghcb->save.sw_exit_code;
+
+	return 0;
+}
+
+int sev_es_test_vc_init(struct kunit *test)
+{
+	int ret;
+
+	if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) {
+		kunit_info(test, "Not a SEV-ES guest. Skipping.");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	memset(&hv_call_krp, 0, sizeof(hv_call_krp));
+	hv_call_krp.entry_handler = hv_call_krp_entry;
+	hv_call_krp.handler = hv_call_krp_ret;
+	hv_call_krp.maxactive = 100;
+	hv_call_krp.data_size = sizeof(unsigned long);
+	hv_call_krp.kp.symbol_name = "sev_es_ghcb_hv_call";
+	hv_call_krp.kp.addr = 0;
+
+	ret = register_kretprobe(&hv_call_krp);
+	if (ret) {
+		kunit_info(test, "Could not register kretprobe. Skipping.");
+		goto out;
+	}
+
+	test->priv = kunit_kzalloc(test, sizeof(u64), GFP_KERNEL);
+	if (!test->priv) {
+		ret = -ENOMEM;
+		kunit_info(test, "Could not allocate. Skipping.");
+		goto out;
+	}
+
+out:
+	return ret;
+}
+
+void sev_es_test_vc_exit(struct kunit *test)
+{
+	if (test->priv)
+		kunit_kfree(test, test->priv);
+
+	if (hv_call_krp.kp.addr)
+		unregister_kretprobe(&hv_call_krp);
+}
+
+#define check_op(kt, ec, op)			\
+do {						\
+	struct kunit *t = (struct kunit *) kt;	\
+	op;					\
+	KUNIT_EXPECT_EQ(t, (typeof(ec)) ec,	\
+		*((typeof(ec) *)(t->priv)));		\
+} while (0)
+
+static void sev_es_nae_cpuid(struct kunit *test)
+{
+	unsigned int cpuid_fn = 0x8000001f;
+
+	check_op(test, SVM_EXIT_CPUID, native_cpuid_eax(cpuid_fn));
+}
+
+static void sev_es_nae_wbinvd(struct kunit *test)
+{
+	check_op(test, SVM_EXIT_WBINVD, wbinvd());
+}
+
+static struct kunit_case sev_es_vc_testcases[] = {
+	KUNIT_CASE(sev_es_nae_cpuid),
+	KUNIT_CASE(sev_es_nae_wbinvd),
+	{}
+};
+
+static struct kunit_suite sev_es_vc_test_suite = {
+	.name = "sev_es_test_vc",
+	.init = sev_es_test_vc_init,
+	.exit = sev_es_test_vc_exit,
+	.test_cases = sev_es_vc_testcases,
+};
+kunit_test_suite(sev_es_vc_test_suite);
--
2.32.0

[PATCH v6 3/4] x86/tests: Add tests for AMD SEV-ES #VC handling Add KUnit based tests to validate Linux's VC handling for instructions accessing registers such as MSR and DR7. These tests: 1. install a kretprobe on the #VC handler (sev_es_ghcb_hv_call, to access GHCB before/after the resulting VMGEXIT). 2. trigger an NAE by accessing either MSR or DR7. 3. check that the kretprobe was hit with the right exit_code available in GHCB.

[Vasant Karasulli]

Signed-off-by: Vasant Karasulli <vkarasulli@suse.de>
---
 arch/x86/tests/sev-test-vc.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/x86/tests/sev-test-vc.c b/arch/x86/tests/sev-test-vc.c
index 9d415b9708dc..b27b9f114a12 100644
--- a/arch/x86/tests/sev-test-vc.c
+++ b/arch/x86/tests/sev-test-vc.c
@@ -7,6 +7,7 @@

 #include <asm/cpufeature.h>
 #include <asm/sev-common.h>
+#include <asm/debugreg.h>
 #include <asm/svm.h>
 #include <kunit/test.h>
 #include <linux/kprobes.h>
@@ -99,9 +100,22 @@ static void sev_es_nae_wbinvd(struct kunit *test)
 	check_op(test, SVM_EXIT_WBINVD, wbinvd());
 }

+static void sev_es_nae_msr(struct kunit *test)
+{
+	check_op(test, SVM_EXIT_MSR, __rdmsr(MSR_IA32_TSC));
+}
+
+static void sev_es_nae_dr7_rw(struct kunit *test)
+{
+	check_op(test, SVM_EXIT_WRITE_DR7,
+		   native_set_debugreg(7, native_get_debugreg(7)));
+}
+
 static struct kunit_case sev_es_vc_testcases[] = {
 	KUNIT_CASE(sev_es_nae_cpuid),
 	KUNIT_CASE(sev_es_nae_wbinvd),
+	KUNIT_CASE(sev_es_nae_msr),
+	KUNIT_CASE(sev_es_nae_dr7_rw),
 	{}
 };

--
2.32.0

[PATCH v6 4/4] x86/tests: Add tests for AMD SEV-ES #VC handling Add KUnit based tests to validate Linux's VC handling for IO instructions. These tests: 1. install a kretprobe on the #VC handler (sev_es_ghcb_hv_call, to access GHCB before/after the resulting VMGEXIT). 2. trigger an NAE by issuing an IO instruction. 3. check that the kretprobe was hit with the right exit_code available in GHCB.

[Vasant Karasulli]

Signed-off-by: Vasant Karasulli <vkarasulli@suse.de>
---
 arch/x86/tests/sev-test-vc.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/arch/x86/tests/sev-test-vc.c b/arch/x86/tests/sev-test-vc.c
index b27b9f114a12..d0e742e2bf9f 100644
--- a/arch/x86/tests/sev-test-vc.c
+++ b/arch/x86/tests/sev-test-vc.c
@@ -8,7 +8,9 @@
 #include <asm/cpufeature.h>
 #include <asm/sev-common.h>
 #include <asm/debugreg.h>
+#include <asm/io.h>
 #include <asm/svm.h>
+#include <asm/apicdef.h>
 #include <kunit/test.h>
 #include <linux/kprobes.h>

@@ -111,11 +113,36 @@ static void sev_es_nae_dr7_rw(struct kunit *test)
 		   native_set_debugreg(7, native_get_debugreg(7)));
 }

+static void sev_es_nae_ioio(struct kunit *test)
+{
+	unsigned long port = 0x80;
+	char val = 0;
+
+	check_op(test, SVM_EXIT_IOIO, val = inb(port));
+	check_op(test, SVM_EXIT_IOIO, outb(val, port));
+	check_op(test, SVM_EXIT_IOIO, insb(port, &val, sizeof(val)));
+	check_op(test, SVM_EXIT_IOIO, outsb(port, &val, sizeof(val)));
+}
+
+static void sev_es_nae_mmio(struct kunit *test)
+{
+	unsigned long lapic_ver_pa = APIC_DEFAULT_PHYS_BASE + APIC_LVR;
+	unsigned long __iomem *lapic = ioremap(lapic_ver_pa, 0x4);
+	unsigned long lapic_version = 0;
+
+	check_op(test, SVM_VMGEXIT_MMIO_READ, lapic_version = *lapic);
+	check_op(test, SVM_VMGEXIT_MMIO_WRITE, *lapic = lapic_version);
+
+	iounmap(lapic);
+}
+
 static struct kunit_case sev_es_vc_testcases[] = {
 	KUNIT_CASE(sev_es_nae_cpuid),
 	KUNIT_CASE(sev_es_nae_wbinvd),
 	KUNIT_CASE(sev_es_nae_msr),
 	KUNIT_CASE(sev_es_nae_dr7_rw),
+	KUNIT_CASE(sev_es_nae_ioio),
+	KUNIT_CASE(sev_es_nae_mmio),
 	{}
 };

--
2.32.0

Re: [PATCH v6 2/4] x86/tests: Add tests for AMD SEV-ES #VC handling Add KUnit based tests to validate Linux's VC handling for instructions cpuid and wbinvd. These tests: 1. install a kretprobe on the #VC handler (sev_es_ghcb_hv_call, to access GHCB before/after the resulting VMGEXIT). 2. trigger an NAE by executing either cpuid or wbinvd. 3. check that the kretprobe was hit with the right exit_code available in GHCB.

[Sean Christopherson]

The shortlog and changelog are all messed up.  Ditto for the other patches in this
series.

On Fri, Mar 18, 2022, Vasant Karasulli wrote:
> Signed-off-by: Vasant Karasulli <vkarasulli@suse.de>
> ---
>  arch/x86/tests/Makefile      |   2 +
>  arch/x86/tests/sev-test-vc.c | 114 +++++++++++++++++++++++++++++++++++
>  2 files changed, 116 insertions(+)
>  create mode 100644 arch/x86/tests/sev-test-vc.c

...

> +int sev_es_test_vc_init(struct kunit *test)
> +{
> +	int ret;
> +
> +	if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) {
> +		kunit_info(test, "Not a SEV-ES guest. Skipping.");
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
> +	memset(&hv_call_krp, 0, sizeof(hv_call_krp));
> +	hv_call_krp.entry_handler = hv_call_krp_entry;
> +	hv_call_krp.handler = hv_call_krp_ret;
> +	hv_call_krp.maxactive = 100;
> +	hv_call_krp.data_size = sizeof(unsigned long);
> +	hv_call_krp.kp.symbol_name = "sev_es_ghcb_hv_call";
> +	hv_call_krp.kp.addr = 0;
> +
> +	ret = register_kretprobe(&hv_call_krp);
> +	if (ret) {
> +		kunit_info(test, "Could not register kretprobe. Skipping.");
> +		goto out;
> +	}
> +
> +	test->priv = kunit_kzalloc(test, sizeof(u64), GFP_KERNEL);

Allocating 8 bytes and storing the pointer an 8-byte field is rather pointless :-)

> +	if (!test->priv) {
> +		ret = -ENOMEM;
> +		kunit_info(test, "Could not allocate. Skipping.");
> +		goto out;
> +	}
> +
> +out:
> +	return ret;
> +}
> +
> +void sev_es_test_vc_exit(struct kunit *test)
> +{
> +	if (test->priv)
> +		kunit_kfree(test, test->priv);
> +
> +	if (hv_call_krp.kp.addr)
> +		unregister_kretprobe(&hv_call_krp);
> +}
> +
> +#define check_op(kt, ec, op)			\
> +do {						\
> +	struct kunit *t = (struct kunit *) kt;	\
> +	op;					\
> +	KUNIT_EXPECT_EQ(t, (typeof(ec)) ec,	\
> +		*((typeof(ec) *)(t->priv)));		\
> +} while (0)
> +
> +static void sev_es_nae_cpuid(struct kunit *test)
> +{
> +	unsigned int cpuid_fn = 0x8000001f;
> +
> +	check_op(test, SVM_EXIT_CPUID, native_cpuid_eax(cpuid_fn));

Are there plans to go beyond basic checks?  Neat idea, but it seems like it will
be prone to bitrot since it requires a somewhat esoteric setup and an opt-in config.
And odds are very good that if the kernel can make it this far as an SEV-ES guest,
it's gotten the basics right.

Re: [PATCH v6 2/4] x86/tests: Add tests for AMD SEV-ES #VC handling Add KUnit based tests to validate Linux's VC handling for instructions cpuid and wbinvd. These tests: 1. install a kretprobe on the #VC handler (sev_es_ghcb_hv_call, to access GHCB before/after the resulting VMGEXIT). 2. trigger an NAE by executing either cpuid or wbinvd. 3. check that the kretprobe was hit with the right exit_code available in GHCB.

[Vasant Karasulli]

On Mi 06-04-22 01:22:55, Sean Christopherson wrote:
> The shortlog and changelog are all messed up.  Ditto for the other patches in this
> series.

I am really sorry about that. I had sent another mail with the same patch version
with subject line corrected.
https://lore.kernel.org/kvm/20220318104646.8313-1-vkarasulli@suse.de/T/#t
>
> On Fri, Mar 18, 2022, Vasant Karasulli wrote:
> > Signed-off-by: Vasant Karasulli <vkarasulli@suse.de>
> > ---
> >  arch/x86/tests/Makefile      |   2 +
> >  arch/x86/tests/sev-test-vc.c | 114 +++++++++++++++++++++++++++++++++++
> >  2 files changed, 116 insertions(+)
> >  create mode 100644 arch/x86/tests/sev-test-vc.c
>
> ...
>
> > +int sev_es_test_vc_init(struct kunit *test)
> > +{
> > +	int ret;
> > +
> > +	if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) {
> > +		kunit_info(test, "Not a SEV-ES guest. Skipping.");
> > +		ret = -EINVAL;
> > +		goto out;
> > +	}
> > +
> > +	memset(&hv_call_krp, 0, sizeof(hv_call_krp));
> > +	hv_call_krp.entry_handler = hv_call_krp_entry;
> > +	hv_call_krp.handler = hv_call_krp_ret;
> > +	hv_call_krp.maxactive = 100;
> > +	hv_call_krp.data_size = sizeof(unsigned long);
> > +	hv_call_krp.kp.symbol_name = "sev_es_ghcb_hv_call";
> > +	hv_call_krp.kp.addr = 0;
> > +
> > +	ret = register_kretprobe(&hv_call_krp);
> > +	if (ret) {
> > +		kunit_info(test, "Could not register kretprobe. Skipping.");
> > +		goto out;
> > +	}
> > +
> > +	test->priv = kunit_kzalloc(test, sizeof(u64), GFP_KERNEL);
>
> Allocating 8 bytes and storing the pointer an 8-byte field is rather pointless :-)

Yes, I will remove this in the next version.
>
> > +	if (!test->priv) {
> > +		ret = -ENOMEM;
> > +		kunit_info(test, "Could not allocate. Skipping.");
> > +		goto out;
> > +	}
> > +
> > +out:
> > +	return ret;
> > +}
> > +
> > +void sev_es_test_vc_exit(struct kunit *test)
> > +{
> > +	if (test->priv)
> > +		kunit_kfree(test, test->priv);
> > +
> > +	if (hv_call_krp.kp.addr)
> > +		unregister_kretprobe(&hv_call_krp);
> > +}
> > +
> > +#define check_op(kt, ec, op)			\
> > +do {						\
> > +	struct kunit *t = (struct kunit *) kt;	\
> > +	op;					\
> > +	KUNIT_EXPECT_EQ(t, (typeof(ec)) ec,	\
> > +		*((typeof(ec) *)(t->priv)));		\
> > +} while (0)
> > +
> > +static void sev_es_nae_cpuid(struct kunit *test)
> > +{
> > +	unsigned int cpuid_fn = 0x8000001f;
> > +
> > +	check_op(test, SVM_EXIT_CPUID, native_cpuid_eax(cpuid_fn));
>
> Are there plans to go beyond basic checks?  Neat idea, but it seems like it will
> be prone to bitrot since it requires a somewhat esoteric setup and an opt-in config.
> And odds are very good that if the kernel can make it this far as an SEV-ES guest,
> it's gotten the basics right.

I will definitely think about adding more checks and performing these checks
early enough in the guest run.

Thanks for your feedback.

Thanks,
Vasant Karasulli
Kernel generalist
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Re: [PATCH v6 2/4] x86/tests: Add tests for AMD SEV-ES #VC handling Add KUnit based tests to validate Linux's VC handling for instructions cpuid and wbinvd. These tests: 1. install a kretprobe on the #VC handler (sev_es_ghcb_hv_call, to access GHCB before/after the resulting VMGEXIT). 2. trigger an NAE by executing either cpuid or wbinvd. 3. check that the kretprobe was hit with the right exit_code available in GHCB.

[Vasant Karasulli]

On Mi 06-04-22 01:22:55, Sean Christopherson wrote:
> > +	if (ret) {
> > +		kunit_info(test, "Could not register kretprobe. Skipping.");
> > +		goto out;
> > +	}
> > +
> > +	test->priv = kunit_kzalloc(test, sizeof(u64), GFP_KERNEL);
>
> Allocating 8 bytes and storing the pointer an 8-byte field is rather pointless :-)
>

Actually it's necessary to allocate memory to test->priv before using according to
https://www.kernel.org/doc/html/latest/dev-tools/kunit/tips.html

> > +	if (!test->priv) {
> > +		ret = -ENOMEM;
> > +		kunit_info(test, "Could not allocate. Skipping.");
> > +		goto out;
> > +	}
> > +

--
Vasant Karasulli
Kernel generalist
www.suse.com<http://www.suse.com>
[https://www.suse.com/assets/img/social-platforms-suse-logo.png]<http://www.suse.com/>
SUSE - Open Source Solutions for Enterprise Servers & Cloud<http://www.suse.com/>
Modernize your infrastructure with SUSE Linux Enterprise servers, cloud technology for IaaS, and SUSE's software-defined storage.
www.suse.com

Re: [PATCH v6 2/4] x86/tests: Add tests for AMD SEV-ES #VC handling Add KUnit based tests to validate Linux's VC handling for instructions cpuid and wbinvd. These tests: 1. install a kretprobe on the #VC handler (sev_es_ghcb_hv_call, to access GHCB before/after the resulting VMGEXIT). 2. trigger an NAE by executing either cpuid or wbinvd. 3. check that the kretprobe was hit with the right exit_code available in GHCB.

[Sean Christopherson]

On Wed, Jun 08, 2022, Vasant Karasulli wrote:
> On Mi 06-04-22 01:22:55, Sean Christopherson wrote:
> > > +	if (ret) {
> > > +		kunit_info(test, "Could not register kretprobe. Skipping.");
> > > +		goto out;
> > > +	}
> > > +
> > > +	test->priv = kunit_kzalloc(test, sizeof(u64), GFP_KERNEL);
> >
> > Allocating 8 bytes and storing the pointer an 8-byte field is rather pointless :-)
> >
> 
> Actually it's necessary to allocate memory to test->priv before using according to
> https://www.kernel.org/doc/html/latest/dev-tools/kunit/tips.html

If priv points at structure of some form, sure, but you're storing a simple value.

Re: [PATCH v6 2/4] x86/tests: Add tests for AMD SEV-ES #VC handling Add KUnit based tests to validate Linux's VC handling for instructions cpuid and wbinvd. These tests: 1. install a kretprobe on the #VC handler (sev_es_ghcb_hv_call, to access GHCB before/after the resulting VMGEXIT). 2. trigger an NAE by executing either cpuid or wbinvd. 3. check that the kretprobe was hit with the right exit_code available in GHCB.

[Vasant Karasulli]

On Mi 08-06-22 14:35:55, Sean Christopherson wrote:
> On Wed, Jun 08, 2022, Vasant Karasulli wrote:
> > On Mi 06-04-22 01:22:55, Sean Christopherson wrote:
> > > > +	if (ret) {
> > > > +		kunit_info(test, "Could not register kretprobe. Skipping.");
> > > > +		goto out;
> > > > +	}
> > > > +
> > > > +	test->priv = kunit_kzalloc(test, sizeof(u64), GFP_KERNEL);
> > >
> > > Allocating 8 bytes and storing the pointer an 8-byte field is rather pointless :-)
> > >
> >
> > Actually it's necessary to allocate memory to test->priv before using according to
> > https://www.kernel.org/doc/html/latest/dev-tools/kunit/tips.html
>
> If priv points at structure of some form, sure, but you're storing a simple value.

Yes, I agree. The reason it was done this way I guess is that type of priv is a
void pointer and storing a u64 value results in a compiler warning:
cast from pointer to integer of different size [-Wpointer-to-int-cast].

Thanks,
Vasant Karasulli
Kernel generalist
www.suse.com<http://www.suse.com>
[https://www.suse.com/assets/img/social-platforms-suse-logo.png]<http://www.suse.com/>
SUSE - Open Source Solutions for Enterprise Servers & Cloud<http://www.suse.com/>
Modernize your infrastructure with SUSE Linux Enterprise servers, cloud technology for IaaS, and SUSE's software-defined storage.
www.suse.com

Re: [PATCH v6 2/4] x86/tests: Add tests for AMD SEV-ES #VC handling Add KUnit based tests to validate Linux's VC handling for instructions cpuid and wbinvd. These tests: 1. install a kretprobe on the #VC handler (sev_es_ghcb_hv_call, to access GHCB before/after the resulting VMGEXIT). 2. trigger an NAE by executing either cpuid or wbinvd. 3. check that the kretprobe was hit with the right exit_code available in GHCB.

[Sean Christopherson]

On Wed, Jun 08, 2022, Vasant Karasulli wrote:
> On Mi 08-06-22 14:35:55, Sean Christopherson wrote:
> > On Wed, Jun 08, 2022, Vasant Karasulli wrote:
> > > On Mi 06-04-22 01:22:55, Sean Christopherson wrote:
> > > > > +	if (ret) {
> > > > > +		kunit_info(test, "Could not register kretprobe. Skipping.");
> > > > > +		goto out;
> > > > > +	}
> > > > > +
> > > > > +	test->priv = kunit_kzalloc(test, sizeof(u64), GFP_KERNEL);
> > > >
> > > > Allocating 8 bytes and storing the pointer an 8-byte field is rather pointless :-)
> > > >
> > >
> > > Actually it's necessary to allocate memory to test->priv before using according to
> > > https://www.kernel.org/doc/html/latest/dev-tools/kunit/tips.html
> >
> > If priv points at structure of some form, sure, but you're storing a simple value.
> 
> Yes, I agree. The reason it was done this way I guess is that type of priv is a
> void pointer and storing a u64 value results in a compiler warning:
> cast from pointer to integer of different size [-Wpointer-to-int-cast].

An intermediate cast to "unsigned long" should make that go away.

Re: [PATCH v6 2/4] x86/tests: Add tests for AMD SEV-ES #VC handling Add KUnit based tests to validate Linux's VC handling for instructions cpuid and wbinvd. These tests: 1. install a kretprobe on the #VC handler (sev_es_ghcb_hv_call, to access GHCB before/after the resulting VMGEXIT). 2. trigger an NAE by executing either cpuid or wbinvd. 3. check that the kretprobe was hit with the right exit_code available in GHCB.

[Vasant Karasulli]

On Mi 08-06-22 19:57:45, Sean Christopherson wrote:
> On Wed, Jun 08, 2022, Vasant Karasulli wrote:
> > On Mi 08-06-22 14:35:55, Sean Christopherson wrote:
> > > On Wed, Jun 08, 2022, Vasant Karasulli wrote:
> > > > On Mi 06-04-22 01:22:55, Sean Christopherson wrote:
> > > > > > +	if (ret) {
> > > > > > +		kunit_info(test, "Could not register kretprobe. Skipping.");
> > > > > > +		goto out;
> > > > > > +	}
> > > > > > +
> > > > > > +	test->priv = kunit_kzalloc(test, sizeof(u64), GFP_KERNEL);
> > > > >
> > > > > Allocating 8 bytes and storing the pointer an 8-byte field is rather pointless :-)
> > > > >
> > > >
> > > > Actually it's necessary to allocate memory to test->priv before using according to
> > > > https://www.kernel.org/doc/html/latest/dev-tools/kunit/tips.html
> > >
> > > If priv points at structure of some form, sure, but you're storing a simple value.
> >
> > Yes, I agree. The reason it was done this way I guess is that type of priv is a
> > void pointer and storing a u64 value results in a compiler warning:
> > cast from pointer to integer of different size [-Wpointer-to-int-cast].
>
> An intermediate cast to "unsigned long" should make that go away.

Yes, intermediate cast satisfied the compiler. Thanks for the tip.

--
Vasant Karasulli
Kernel generalist
www.suse.com<http://www.suse.com>
[https://www.suse.com/assets/img/social-platforms-suse-logo.png]<http://www.suse.com/>
SUSE - Open Source Solutions for Enterprise Servers & Cloud<http://www.suse.com/>
Modernize your infrastructure with SUSE Linux Enterprise servers, cloud technology for IaaS, and SUSE's software-defined storage.
www.suse.com

[PATCH v6 0/4] x86/tests: Add tests for AMD SEV-ES #VC handling

[Vasant Karasulli]

Hi All,

   This is the version 6 of the patch written to add tests for
   AMD SEV-ES #VC handling. This version attempts to
   address review comments to the previous version of the patch in
   https://lore.kernel.org/kvm/20220208162623.18368-1-vkarasulli@suse.de/.

   Changes in this version:
   1. The patch in the previous version is split into 4 parts.
   2. Constants in function sev_es_nae_mmio are replaced by macros.

PS: I am resending this version because I made a mistake in the subject.
Apologies for the spam.

Thanks,
Vasant


Vasant Karasulli (4):
  x86/tests: Add Kconfig options for testing AMD SEV related features.
  x86/tests: Add KUnit based tests to validate Linux's VC handling for
    instructions cpuid and wbinvd. These tests: 1. install a kretprobe
    on the #VC handler (sev_es_ghcb_hv_call, to    access GHCB
    before/after the resulting VMGEXIT). 2. trigger an NAE by executing
    either cpuid or wbinvd. 3. check that the kretprobe was hit with the
    right exit_code available    in GHCB.
  x86/tests: Add KUnit based tests to validate Linux's VC handling for
      instructions accessing registers such as MSR and DR7. These tests:
        1. install a kretprobe on the #VC handler (sev_es_ghcb_hv_call,
    to        access GHCB before/after the resulting VMGEXIT).     2.
    trigger an NAE by accessing either MSR or DR7.     3. check that the
    kretprobe was hit with the right exit_code available        in GHCB.
  x86/tests: Add KUnit based tests to validate Linux's VC handling for
          IO instructions. These tests:         1. install a kretprobe
    on the #VC handler (sev_es_ghcb_hv_call, to            access GHCB
    before/after the resulting VMGEXIT).         2. trigger an NAE by
    issuing an IO instruction.         3. check that the kretprobe was
    hit with the right exit_code available            in GHCB.

 arch/x86/Kbuild              |   2 +
 arch/x86/Kconfig.debug       |  16 ++++
 arch/x86/kernel/Makefile     |   7 ++
 arch/x86/tests/Makefile      |   3 +
 arch/x86/tests/sev-test-vc.c | 155 +++++++++++++++++++++++++++++++++++
 5 files changed, 183 insertions(+)
 create mode 100644 arch/x86/tests/Makefile
 create mode 100644 arch/x86/tests/sev-test-vc.c


base-commit: 09688c0166e76ce2fb85e86b9d99be8b0084cdf9
prerequisite-patch-id: b74bc39d7ca69ad86b5f9090047c44ab039f4622
prerequisite-patch-id: a53a291b59b4ceaffa25a9a08dfa08b5a78a01b9
--
2.32.0