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x86/sev-es: Handle MSR events 

Implement a handler for #VC exceptions caused by RDMSR/WRMSR
instructions.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
[ jroedel@suse.de: Adapt to #VC handling infrastructure. ]
Co-developed-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-52-joro@8bytes.org
This commit is contained in:
Tom Lendacky 2020-09-07 15:15:52 +02:00 committed by Borislav Petkov
parent 0118b604c2
commit a4afa6081c
1 changed files with 28 additions and 0 deletions
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28
arch/x86/kernel/sev-es.c
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@ -393,6 +393,31 @@ static bool vc_slow_virt_to_phys(struct ghcb *ghcb, struct es_em_ctxt *ctxt,
/* Include code shared with pre-decompression boot stage */
#include "sev-es-shared.c"
static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
{
struct pt_regs *regs = ctxt->regs;
enum es_result ret;
u64 exit_info_1;
/* Is it a WRMSR? */
exit_info_1 = (ctxt->insn.opcode.bytes[1] == 0x30) ? 1 : 0;
ghcb_set_rcx(ghcb, regs->cx);
if (exit_info_1) {
ghcb_set_rax(ghcb, regs->ax);
ghcb_set_rdx(ghcb, regs->dx);
}
ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_MSR, exit_info_1, 0);
if ((ret == ES_OK) && (!exit_info_1)) {
regs->ax = ghcb->save.rax;
regs->dx = ghcb->save.rdx;
}
return ret;
}
/*
* This function runs on the first #VC exception after the kernel
* switched to virtual addresses.
@ -756,6 +781,9 @@ static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt,
case SVM_EXIT_IOIO:
result = vc_handle_ioio(ghcb, ctxt);
break;
case SVM_EXIT_MSR:
result = vc_handle_msr(ghcb, ctxt);
break;
case SVM_EXIT_NPF:
result = vc_handle_mmio(ghcb, ctxt);
break;