Commit 8bca85cc authored by Borislav Petkov (AMD)'s avatar Borislav Petkov (AMD)
Browse files

x86/sev: Cleanup vc_handle_msr() 



Carve out the MSR_SVSM_CAA into a helper with the suggestion that
upcoming future users should do the same. Rename that silly exit_info_1
into what it actually means in this function - whether the MSR access is
a read or a write.

No functional changes.

Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: default avatarPankaj Gupta <pankaj.gupta@amd.com>
Link: https://lore.kernel.org/r/20241106172647.GAZyum1zngPDwyD2IJ@fat_crate.local
parent 3074152e

arch/x86/coco/sev/core.c

+19 −15
Original line number Diff line number Diff line
@@ -1406,18 +1406,10 @@ int __init sev_es_efi_map_ghcbs(pgd_t *pgd) 
	return 0;

}



static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt)

/* Writes to the SVSM CAA MSR are ignored */

static enum es_result __vc_handle_msr_caa(struct pt_regs *regs, bool write)

{

	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;



	if (regs->cx == MSR_SVSM_CAA) {

		/* Writes to the SVSM CAA msr are ignored */

		if (exit_info_1)

	if (write)

		return ES_OK;



	regs->ax = lower_32_bits(this_cpu_read(svsm_caa_pa));
@@ -1426,15 +1418,27 @@ static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt) 
	return ES_OK;

}



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;

	bool write;



	/* Is it a WRMSR? */

	write = ctxt->insn.opcode.bytes[1] == 0x30;



	if (regs->cx == MSR_SVSM_CAA)

		return __vc_handle_msr_caa(regs, write);



	ghcb_set_rcx(ghcb, regs->cx);

	if (exit_info_1) {

	if (write) {

		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);

	ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_MSR, write, 0);



	if ((ret == ES_OK) && (!exit_info_1)) {

	if ((ret == ES_OK) && !write) {

		regs->ax = ghcb->save.rax;

		regs->dx = ghcb->save.rdx;

	}