Commit 32071fa3 authored by Sean Christopherson's avatar Sean Christopherson
Browse files

KVM: SVM: Track the per-CPU host save area as a VMCB pointer 

The host save area is a VMCB, track it as such to help readers follow
along, but mostly to cleanup/simplify the retrieval of the SEV-ES host
save area.

Note, the compile-time assertion that

  offsetof(struct vmcb, save) == EXPECTED_VMCB_CONTROL_AREA_SIZE

ensures that the SEV-ES save area is indeed at offset 0x400 (whoever added
the expected/architectural VMCB offsets apparently likes decimal).

No functional change intended.

Link: https://lore.kernel.org/r/20240802204511.352017-4-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
parent 1b5ef14d

arch/x86/kvm/svm/svm.c

+8 −7
Original line number Diff line number Diff line
@@ -573,7 +573,7 @@ static void __svm_write_tsc_multiplier(u64 multiplier) 


static __always_inline struct sev_es_save_area *sev_es_host_save_area(struct svm_cpu_data *sd)

{

	return page_address(sd->save_area) + 0x400;

	return &sd->save_area->host_sev_es_save;

}



static inline void kvm_cpu_svm_disable(void)
@@ -696,7 +696,7 @@ static void svm_cpu_uninit(int cpu) 
		return;



	kfree(sd->sev_vmcbs);

	__free_page(sd->save_area);

	__free_page(__sme_pa_to_page(sd->save_area_pa));

	sd->save_area_pa = 0;

	sd->save_area = NULL;

}
@@ -704,23 +704,24 @@ static void svm_cpu_uninit(int cpu) 
static int svm_cpu_init(int cpu)

{

	struct svm_cpu_data *sd = per_cpu_ptr(&svm_data, cpu);

	struct page *save_area_page;

	int ret = -ENOMEM;



	memset(sd, 0, sizeof(struct svm_cpu_data));

	sd->save_area = snp_safe_alloc_page_node(cpu_to_node(cpu), GFP_KERNEL);

	if (!sd->save_area)

	save_area_page = snp_safe_alloc_page_node(cpu_to_node(cpu), GFP_KERNEL);

	if (!save_area_page)

		return ret;



	ret = sev_cpu_init(sd);

	if (ret)

		goto free_save_area;



	sd->save_area_pa = __sme_page_pa(sd->save_area);

	sd->save_area = page_address(save_area_page);

	sd->save_area_pa = __sme_page_pa(save_area_page);

	return 0;



free_save_area:

	__free_page(sd->save_area);

	sd->save_area = NULL;

	__free_page(save_area_page);

	return ret;



}

arch/x86/kvm/svm/svm.h

+1 −1
Original line number Diff line number Diff line
@@ -335,7 +335,7 @@ struct svm_cpu_data { 
	u32 next_asid;

	u32 min_asid;



	struct page *save_area;

	struct vmcb *save_area;

	unsigned long save_area_pa;



	struct vmcb *current_vmcb;