GHCB spec specifies that an SNP guest can submit PSMASH/UNSMASH hints
to hypervisor via PSC requests. Include a test to create such a PSC
request where KUT-SNP guest requests hypervisor to PSMASH/UNSMASH
2M ranges, to ensure hypervisor handles these requests without any
issues.
Signed-off-by: Pavan Kumar Paluri <papaluri@xxxxxxx>
---
lib/x86/amd_sev.c | 10 +++----
lib/x86/amd_sev.h | 5 ++++
x86/amd_sev.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 76 insertions(+), 5 deletions(-)
diff --git a/lib/x86/amd_sev.c b/lib/x86/amd_sev.c
index c2f2a3f43193..468ed9eef943 100644
--- a/lib/x86/amd_sev.c
+++ b/lib/x86/amd_sev.c
@@ -355,8 +355,8 @@ static bool pvalidate_failed(int result, bool allow_noupdate)
return false;
}
-static void pvalidate_pages(struct snp_psc_desc *desc, unsigned long *vaddr_arr,
- bool allow_noupdate)
+void pvalidate_pages(struct snp_psc_desc *desc, unsigned long *vaddr_arr,
+ bool allow_noupdate)
{
struct psc_entry *entry;
int ret, i;
@@ -403,7 +403,7 @@ static int sev_ghcb_hv_call(struct ghcb *ghcb, u64 exit_code,
return verify_exception(ghcb);
}
-static int vmgexit_psc(struct snp_psc_desc *desc, struct ghcb *ghcb)
+int vmgexit_psc(struct snp_psc_desc *desc, struct ghcb *ghcb)
{
int cur_entry, end_entry, ret = 0;
struct snp_psc_desc *data;
@@ -457,8 +457,8 @@ static int vmgexit_psc(struct snp_psc_desc *desc, struct ghcb *ghcb)
return ret;
}
-static void add_psc_entry(struct snp_psc_desc *desc, u8 idx, u8 op, unsigned long vaddr,
- bool large_entry, u16 cur_page_offset)
+void add_psc_entry(struct snp_psc_desc *desc, u8 idx, u8 op, unsigned long vaddr,
+ bool large_entry, u16 cur_page_offset)
{
struct psc_hdr *hdr = &desc->hdr;
struct psc_entry *entry = &desc->entries[idx];
diff --git a/lib/x86/amd_sev.h b/lib/x86/amd_sev.h
index e180a269fb63..8357a658d47d 100644
--- a/lib/x86/amd_sev.h
+++ b/lib/x86/amd_sev.h
@@ -247,6 +247,11 @@ unsigned long __sev_set_pages_state(struct snp_psc_desc *desc, unsigned long vad
struct ghcb *ghcb, bool large_entry,
bool allow_noupdate);
void vc_ghcb_invalidate(struct ghcb *ghcb);
+void pvalidate_pages(struct snp_psc_desc *desc, unsigned long *vaddr_arr,
+ bool allow_noupdate);
+int vmgexit_psc(struct snp_psc_desc *desc, struct ghcb *ghcb);
+void add_psc_entry(struct snp_psc_desc *desc, u8 idx, u8 op,
+ unsigned long vaddr, bool large_entry, u16 offset);
unsigned long long get_amd_sev_c_bit_mask(void);
unsigned long long get_amd_sev_addr_upperbound(void);
diff --git a/x86/amd_sev.c b/x86/amd_sev.c
index ae19f8ad6cc8..bd369e5cada7 100644
--- a/x86/amd_sev.c
+++ b/x86/amd_sev.c
@@ -366,6 +366,71 @@ static void test_sev_psc_intermix_to_shared(void)
test_sev_psc_intermix(false);
}
+static void test_sev_snp_psmash(void)
+{
+ int ret;
+ unsigned long vaddr, vaddr_arr[3];
+ struct snp_psc_desc desc = {0};
+ struct ghcb *ghcb = (struct ghcb *)(rdmsr(SEV_ES_GHCB_MSR_INDEX));
+
+ report_info("TEST: PSMASH and UNSMASH operations on 2M range");
+
+ vaddr = (unsigned long)vmalloc_pages(SEV_ALLOC_PAGE_COUNT,
+ SEV_ALLOC_ORDER, RMP_PG_SIZE_2M);
+
+ /*
+ * Create a PSC request for first PSC entry where:
+ * - guest issues an UNSMASH on a 2M private range.
+ * Hypervisor treats an UNSMASH hint from guest as a nop.
+ * So it is expected that the state of pages after conversion to
+ * be in the same state as before.
+ */
+ vaddr_arr[0] = vaddr;
+ add_psc_entry(&desc, 0, SNP_PAGE_STATE_UNSMASH, vaddr_arr[0],
+ true, 0);
+
+ /*
+ * Create a PSC request for second PSC entry where:
+ * - guest issues a PSMASH on the next 2M private range.
+ * Hypervisor should also treat PSMASH hint from guest as a nop.
+ */
+ vaddr_arr[1] = vaddr + LARGE_PAGE_SIZE;
+ add_psc_entry(&desc, 1, SNP_PAGE_STATE_PSMASH, vaddr_arr[1],
+ true, 0);
+
+ /*
+ * For 3rd PSC entry:
+ * Perform an UNSMASH on the PSMASH'd entry where:
+ * - guest now issues an UNSMASH on a 2M private PSMASH'd entry,
+ * but since a PSMASH/UNSMASH are noops, states of these pages
+ * should be in their original (private) states.
+ */
+ vaddr_arr[2] = vaddr_arr[1];
+ add_psc_entry(&desc, 2, SNP_PAGE_STATE_UNSMASH, vaddr_arr[2],
+ true, 0);
+
+ ret = vmgexit_psc(&desc, ghcb);
+
+ assert_msg(!ret, "VMGEXIT failed with ret value: %d", ret);
+
+ /*
+ * Ensure the page states are still in the original (private)
+ * state after hypervisor handled PSMASH/UNSMASH operations.
+ */
+ report(is_validated_private_page(vaddr, RMP_PG_SIZE_2M),
+ "Expected page state: Private");
+
+ report(is_validated_private_page(vaddr + LARGE_PAGE_SIZE,
+ RMP_PG_SIZE_2M),
+ "Expected page state: Private");
+
+ pvalidate_pages(&desc, vaddr_arr, true);
+
+ /* Free up all the used pages */
+ snp_free_pages(SEV_ALLOC_ORDER, SEV_ALLOC_PAGE_COUNT, vaddr,
+ ghcb, true);
+}
+
int main(void)
{
int rtn;
@@ -387,6 +452,7 @@ int main(void)
test_sev_psc_ghcb_nae();
test_sev_psc_intermix_to_private();
test_sev_psc_intermix_to_shared();
+ test_sev_snp_psmash();
}
return report_summary();
--
2.34.1
