From 007faec014cb5d26983c1f86fd08c6539b41392e Mon Sep 17 00:00:00 2001 From: Tianyu Lan Date: Mon, 25 Oct 2021 08:21:10 -0400 Subject: x86/sev: Expose sev_es_ghcb_hv_call() for use by HyperV Hyper-V needs to issue the GHCB HV call in order to read/write MSRs in Isolation VMs. For that, expose sev_es_ghcb_hv_call(). The Hyper-V Isolation VMs are unenlightened guests and run a paravisor at VMPL0 for communicating. GHCB pages are being allocated and set up by that paravisor. Linux gets the GHCB page's physical address via MSR_AMD64_SEV_ES_GHCB from the paravisor and should not change it. Add a @set_ghcb_msr parameter to sev_es_ghcb_hv_call() to control whether the function should set the GHCB's address prior to the call or not and export that function for use by HyperV. [ bp: - Massage commit message - add a struct ghcb forward declaration to fix randconfig builds. ] Signed-off-by: Tianyu Lan Signed-off-by: Borislav Petkov Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20211025122116.264793-6-ltykernel@gmail.com --- arch/x86/include/asm/sev.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'arch/x86/include') diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index fa5cd05d3b5b..ec060c433589 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -53,6 +53,7 @@ static inline u64 lower_bits(u64 val, unsigned int bits) struct real_mode_header; enum stack_type; +struct ghcb; /* Early IDT entry points for #VC handler */ extern void vc_no_ghcb(void); @@ -81,6 +82,11 @@ static __always_inline void sev_es_nmi_complete(void) __sev_es_nmi_complete(); } extern int __init sev_es_efi_map_ghcbs(pgd_t *pgd); +extern enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb, + bool set_ghcb_msr, + struct es_em_ctxt *ctxt, + u64 exit_code, u64 exit_info_1, + u64 exit_info_2); #else static inline void sev_es_ist_enter(struct pt_regs *regs) { } static inline void sev_es_ist_exit(void) { } -- cgit v1.3-18-gd494