[RFC PATCH v3 4/4] kvmppc: Handle memory plug/unplug to secure VM

[Bharata B Rao <bharata@xxxxxxxxxxxxx>]

Register the new memslot with UV during plug and unregister
the memslot during unplug.

Signed-off-by: Bharata B Rao <bharata@xxxxxxxxxxxxx>
---
 arch/powerpc/include/asm/ucall-api.h        |  7 +++++++
 arch/powerpc/include/uapi/asm/uapi_uvcall.h |  1 +
 arch/powerpc/kvm/book3s_hv.c                | 19 +++++++++++++++++++
 3 files changed, 27 insertions(+)

diff --git a/arch/powerpc/include/asm/ucall-api.h b/arch/powerpc/include/asm/ucall-api.h
index d266670229cb..cbb8bb38eb8b 100644
--- a/arch/powerpc/include/asm/ucall-api.h
+++ b/arch/powerpc/include/asm/ucall-api.h
@@ -82,5 +82,12 @@ static inline int uv_register_mem_slot(u64 lpid, u64 start_gpa, u64 size,
 	return plpar_ucall(UV_REGISTER_MEM_SLOT, retbuf, lpid, start_gpa,
 			   size, flags, slotid);
 }
+
+static inline int uv_unregister_mem_slot(u64 lpid, u64 slotid)
+{
+	unsigned long retbuf[PLPAR_UCALL_BUFSIZE];
+
+	return plpar_ucall(UV_UNREGISTER_MEM_SLOT, retbuf, lpid, slotid);
+}
 #endif	/* __ASSEMBLY__ */
 #endif	/* _ASM_POWERPC_UCALL_API_H */
diff --git a/arch/powerpc/include/uapi/asm/uapi_uvcall.h b/arch/powerpc/include/uapi/asm/uapi_uvcall.h
index 79a11a6ee436..60e44c7b58c4 100644
--- a/arch/powerpc/include/uapi/asm/uapi_uvcall.h
+++ b/arch/powerpc/include/uapi/asm/uapi_uvcall.h
@@ -13,6 +13,7 @@
 #define UV_RESTRICTED_SPR_READ 0xf10C
 #define UV_RETURN	0xf11C
 #define UV_REGISTER_MEM_SLOT    0xF120
+#define UV_UNREGISTER_MEM_SLOT    0xF124
 #define UV_PAGE_IN	0xF128
 #define UV_PAGE_OUT	0xF12C
 
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 1dfb42ac9626..61e36c4516d5 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -76,6 +76,7 @@
 #include <asm/xive.h>
 #include <asm/kvm_host.h>
 #include <asm/kvm_book3s_hmm.h>
+#include <asm/ucall-api.h>
 
 #include "book3s.h"
 
@@ -4433,6 +4434,24 @@ static void kvmppc_core_commit_memory_region_hv(struct kvm *kvm,
 	if (change == KVM_MR_FLAGS_ONLY && kvm_is_radix(kvm) &&
 	    ((new->flags ^ old->flags) & KVM_MEM_LOG_DIRTY_PAGES))
 		kvmppc_radix_flush_memslot(kvm, old);
+	/*
+	 * If UV hasn't yet called H_SVM_INIT_START, don't register memslots.
+	 */
+	if (!kvm->arch.secure_guest)
+		return;
+
+	/*
+	 * TODO: Handle KVM_MR_MOVE
+	 */
+	if (change == KVM_MR_CREATE) {
+		uv_register_mem_slot(kvm->arch.lpid,
+					   new->base_gfn << PAGE_SHIFT,
+					   new->npages * PAGE_SIZE,
+					   0,
+					   new->id);
+	} else if (change == KVM_MR_DELETE) {
+		uv_unregister_mem_slot(kvm->arch.lpid, old->id);
+	}
 }
 
 /*
-- 
2.17.1