From: Sean Christopherson <seanjc@google.com>
Date: Tue, 7 Dec 2021 22:09:26 +0000
Patch-mainline: v5.18-rc1
Subject: KVM: x86: Add checks for reserved-to-zero Hyper-V hypercall fields
Git-commit: 413af6601f7613c07d8c36b57e184d7841ace43a
References: bsc#1206453
Add checks for the three fields in Hyper-V's hypercall params that must
be zero. Per the TLFS, HV_STATUS_INVALID_HYPERCALL_INPUT is returned if
"A reserved bit in the specified hypercall input value is non-zero."
Note, some versions of the TLFS have an off-by-one bug for the last
reserved field, and define it as being bits 64:60. See
https://github.com/MicrosoftDocs/Virtualization-Documentation/pull/1682.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20211207220926.718794-9-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Olaf Hering <ohering@suse.de>
---
arch/x86/kvm/hyperv.c | 5 +++++
include/asm-generic/hyperv-tlfs.h | 6 ++++++
2 files changed, 11 insertions(+)
diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
--- a/include/asm-generic/hyperv-tlfs.h
+++ b/include/asm-generic/hyperv-tlfs.h
@@ -184,11 +184,17 @@ enum HV_GENERIC_SET_FORMAT {
#define HV_HYPERCALL_FAST_BIT BIT(16)
#define HV_HYPERCALL_VARHEAD_OFFSET 17
#define HV_HYPERCALL_VARHEAD_MASK GENMASK_ULL(26, 17)
+#define HV_HYPERCALL_RSVD0_MASK GENMASK_ULL(31, 27)
#define HV_HYPERCALL_REP_COMP_OFFSET 32
#define HV_HYPERCALL_REP_COMP_1 BIT_ULL(32)
#define HV_HYPERCALL_REP_COMP_MASK GENMASK_ULL(43, 32)
+#define HV_HYPERCALL_RSVD1_MASK GENMASK_ULL(47, 44)
#define HV_HYPERCALL_REP_START_OFFSET 48
#define HV_HYPERCALL_REP_START_MASK GENMASK_ULL(59, 48)
+#define HV_HYPERCALL_RSVD2_MASK GENMASK_ULL(63, 60)
+#define HV_HYPERCALL_RSVD_MASK (HV_HYPERCALL_RSVD0_MASK | \
+ HV_HYPERCALL_RSVD1_MASK | \
+ HV_HYPERCALL_RSVD2_MASK)
/* hypercall status code */
#define HV_STATUS_SUCCESS 0