1 files changed, 99 insertions, 0 deletions
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 39c87469ee0b..e3fca8615fe8 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -556,6 +556,105 @@ static u64 get_jump_table_addr(void)
 	return ret;
 }
 
+static void pvalidate_pages(unsigned long vaddr, unsigned int npages, bool validate)
+{
+	unsigned long vaddr_end;
+	int rc;
+
+	vaddr = vaddr & PAGE_MASK;
+	vaddr_end = vaddr + (npages << PAGE_SHIFT);
+
+	while (vaddr < vaddr_end) {
+		rc = pvalidate(vaddr, RMP_PG_SIZE_4K, validate);
+		if (WARN(rc, "Failed to validate address 0x%lx ret %d", vaddr, rc))
+			sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE);
+
+		vaddr = vaddr + PAGE_SIZE;
+	}
+}
+
+static void __init early_set_pages_state(unsigned long paddr, unsigned int npages, enum psc_op op)
+{
+	unsigned long paddr_end;
+	u64 val;
+
+	paddr = paddr & PAGE_MASK;
+	paddr_end = paddr + (npages << PAGE_SHIFT);
+
+	while (paddr < paddr_end) {
+		/*
+		 * Use the MSR protocol because this function can be called before
+		 * the GHCB is established.
+		 */
+		sev_es_wr_ghcb_msr(GHCB_MSR_PSC_REQ_GFN(paddr >> PAGE_SHIFT, op));
+		VMGEXIT();
+
+		val = sev_es_rd_ghcb_msr();
+
+		if (WARN(GHCB_RESP_CODE(val) != GHCB_MSR_PSC_RESP,
+			 "Wrong PSC response code: 0x%x\n",
+			 (unsigned int)GHCB_RESP_CODE(val)))
+			goto e_term;
+
+		if (WARN(GHCB_MSR_PSC_RESP_VAL(val),
+			 "Failed to change page state to '%s' paddr 0x%lx error 0x%llx\n",
+			 op == SNP_PAGE_STATE_PRIVATE ? "private" : "shared",
+			 paddr, GHCB_MSR_PSC_RESP_VAL(val)))
+			goto e_term;
+
+		paddr = paddr + PAGE_SIZE;
+	}
+
+	return;
+
+e_term:
+	sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC);
+}
+
+void __init early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr,
+					 unsigned int npages)
+{
+	if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+		return;
+
+	 /*
+	  * Ask the hypervisor to mark the memory pages as private in the RMP
+	  * table.
+	  */
+	early_set_pages_state(paddr, npages, SNP_PAGE_STATE_PRIVATE);
+
+	/* Validate the memory pages after they've been added in the RMP table. */
+	pvalidate_pages(vaddr, npages, true);
+}
+
+void __init early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr,
+					unsigned int npages)
+{
+	if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
+		return;
+
+	/* Invalidate the memory pages before they are marked shared in the RMP table. */
+	pvalidate_pages(vaddr, npages, false);
+
+	 /* Ask hypervisor to mark the memory pages shared in the RMP table. */
+	early_set_pages_state(paddr, npages, SNP_PAGE_STATE_SHARED);
+}
+
+void __init snp_prep_memory(unsigned long paddr, unsigned int sz, enum psc_op op)
+{
+	unsigned long vaddr, npages;
+
+	vaddr = (unsigned long)__va(paddr);
+	npages = PAGE_ALIGN(sz) >> PAGE_SHIFT;
+
+	if (op == SNP_PAGE_STATE_PRIVATE)
+		early_snp_set_memory_private(vaddr, paddr, npages);
+	else if (op == SNP_PAGE_STATE_SHARED)
+		early_snp_set_memory_shared(vaddr, paddr, npages);
+	else
+		WARN(1, "invalid memory op %d\n", op);
+}
+
 int sev_es_setup_ap_jump_table(struct real_mode_header *rmh)
 {
 	u16 startup_cs, startup_ip;