Re: [PATCH Part2 v5 05/45] x86/sev: Add helper functions for RMPUPDATE and PSMASH instruction

From: Brijesh Singh
Date: Mon Sep 27 2021 - 12:06:14 EST

On 9/24/21 9:04 AM, Borislav Petkov wrote:
On Fri, Aug 20, 2021 at 10:58:38AM -0500, Brijesh Singh wrote:
The RMPUPDATE instruction writes a new RMP entry in the RMP Table. The
hypervisor will use the instruction to add pages to the RMP table. See
APM3 for details on the instruction operations.

The PSMASH instruction expands a 2MB RMP entry into a corresponding set of
contiguous 4KB-Page RMP entries. The hypervisor will use this instruction
to adjust the RMP entry without invalidating the previous RMP entry.

Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
arch/x86/include/asm/sev.h | 11 ++++++
arch/x86/kernel/sev.c | 72 ++++++++++++++++++++++++++++++++++++++
2 files changed, 83 insertions(+)

diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 5b1a6a075c47..92ced9626e95 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -78,7 +78,9 @@ extern bool handle_vc_boot_ghcb(struct pt_regs *regs);
/* RMP page size */
#define RMP_PG_SIZE_4K 0
+#define RMP_PG_SIZE_2M 1
#define RMP_TO_X86_PG_LEVEL(level) (((level) == RMP_PG_SIZE_4K) ? PG_LEVEL_4K : PG_LEVEL_2M)
+#define X86_TO_RMP_PG_LEVEL(level) (((level) == PG_LEVEL_4K) ? RMP_PG_SIZE_4K : RMP_PG_SIZE_2M)
* The RMP entry format is not architectural. The format is defined in PPR
@@ -107,6 +109,15 @@ struct __packed rmpentry {
+struct rmpupdate {

Function is called the same way - maybe this should be called
rmpupdate_desc or so.


+ return ret;

That's for kvm?




Both exports for kvm I assume?

yes, both KVM and CCP drivers need them.