Commit db912b89 authored by Nuno Das Neves's avatar Nuno Das Neves Committed by Wei Liu
Browse files

hyperv: Change hv_root_partition into a function 



Introduce hv_curr_partition_type to store the partition type
as an enum.

Right now this is limited to guest or root partition, but there will
be other kinds in future and the enum is easily extensible.

Set up hv_curr_partition_type early in Hyper-V initialization with
hv_identify_partition_type(). hv_root_partition() just queries this
value, and shouldn't be called before that.

Making this check into a function sets the stage for adding a config
option to gate the compilation of root partition code. In particular,
hv_root_partition() can be stubbed out always be false if root
partition support isn't desired.

Signed-off-by: default avatarNuno Das Neves <nunodasneves@linux.microsoft.com>
Reviewed-by: default avatarEaswar Hariharan <eahariha@linux.microsoft.com>
Reviewed-by: default avatarMichael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/1740167795-13296-3-git-send-email-nunodasneves@linux.microsoft.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
Message-ID: <1740167795-13296-3-git-send-email-nunodasneves@linux.microsoft.com>
parent 9d8731a1

arch/arm64/hyperv/mshyperv.c

+2 −0
Original line number Diff line number Diff line
@@ -61,6 +61,8 @@ static int __init hyperv_init(void) 
		ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints,

		ms_hyperv.misc_features);



	hv_identify_partition_type();



	ret = hv_common_init();

	if (ret)

		return ret;

arch/x86/hyperv/hv_init.c

+5 −5
Original line number Diff line number Diff line
@@ -90,7 +90,7 @@ static int hv_cpu_init(unsigned int cpu) 
		return 0;



	hvp = &hv_vp_assist_page[cpu];

	if (hv_root_partition) {

	if (hv_root_partition()) {

		/*

		 * For root partition we get the hypervisor provided VP assist

		 * page, instead of allocating a new page.
@@ -242,7 +242,7 @@ static int hv_cpu_die(unsigned int cpu) 


	if (hv_vp_assist_page && hv_vp_assist_page[cpu]) {

		union hv_vp_assist_msr_contents msr = { 0 };

		if (hv_root_partition) {

		if (hv_root_partition()) {

			/*

			 * For root partition the VP assist page is mapped to

			 * hypervisor provided page, and thus we unmap the
@@ -317,7 +317,7 @@ static int hv_suspend(void) 
	union hv_x64_msr_hypercall_contents hypercall_msr;

	int ret;



	if (hv_root_partition)

	if (hv_root_partition())

		return -EPERM;



	/*
@@ -518,7 +518,7 @@ void __init hyperv_init(void) 
	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);

	hypercall_msr.enable = 1;



	if (hv_root_partition) {

	if (hv_root_partition()) {

		struct page *pg;

		void *src;
@@ -592,7 +592,7 @@ void __init hyperv_init(void) 
	 * If we're running as root, we want to create our own PCI MSI domain.

	 * We can't set this in hv_pci_init because that would be too late.

	 */

	if (hv_root_partition)

	if (hv_root_partition())

		x86_init.irqs.create_pci_msi_domain = hv_create_pci_msi_domain;

#endif

arch/x86/kernel/cpu/mshyperv.c

+2 −22
Original line number Diff line number Diff line
@@ -33,8 +33,6 @@ 
#include <asm/numa.h>

#include <asm/svm.h>



/* Is Linux running as the root partition? */

bool hv_root_partition;

/* Is Linux running on nested Microsoft Hypervisor */

bool hv_nested;

struct ms_hyperv_info ms_hyperv;
@@ -451,25 +449,7 @@ static void __init ms_hyperv_init_platform(void) 
	pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n",

		 ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);



	/*

	 * Check CPU management privilege.

	 *

	 * To mirror what Windows does we should extract CPU management

	 * features and use the ReservedIdentityBit to detect if Linux is the

	 * root partition. But that requires negotiating CPU management

	 * interface (a process to be finalized). For now, use the privilege

	 * flag as the indicator for running as root.

	 *

	 * Hyper-V should never specify running as root and as a Confidential

	 * VM. But to protect against a compromised/malicious Hyper-V trying

	 * to exploit root behavior to expose Confidential VM memory, ignore

	 * the root partition setting if also a Confidential VM.

	 */

	if ((ms_hyperv.priv_high & HV_CPU_MANAGEMENT) &&

	    !(ms_hyperv.priv_high & HV_ISOLATION)) {

		hv_root_partition = true;

		pr_info("Hyper-V: running as root partition\n");

	}

	hv_identify_partition_type();



	if (ms_hyperv.hints & HV_X64_HYPERV_NESTED) {

		hv_nested = true;
@@ -618,7 +598,7 @@ static void __init ms_hyperv_init_platform(void) 


# ifdef CONFIG_SMP

	smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu;

	if (hv_root_partition ||

	if (hv_root_partition() ||

	    (!ms_hyperv.paravisor_present && hv_isolation_type_snp()))

		smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus;

# endif

drivers/clocksource/hyperv_timer.c

+2 −2
Original line number Diff line number Diff line
@@ -582,7 +582,7 @@ static void __init hv_init_tsc_clocksource(void) 
	 * mapped.

	 */

	tsc_msr.as_uint64 = hv_get_msr(HV_MSR_REFERENCE_TSC);

	if (hv_root_partition)

	if (hv_root_partition())

		tsc_pfn = tsc_msr.pfn;

	else

		tsc_pfn = HVPFN_DOWN(virt_to_phys(tsc_page));
@@ -627,7 +627,7 @@ void __init hv_remap_tsc_clocksource(void) 
	if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE))

		return;



	if (!hv_root_partition) {

	if (!hv_root_partition()) {

		WARN(1, "%s: attempt to remap TSC page in guest partition\n",

		     __func__);

		return;

drivers/hv/hv.c

+5 −5
Original line number Diff line number Diff line
@@ -144,7 +144,7 @@ int hv_synic_alloc(void) 
		 * Synic message and event pages are allocated by paravisor.

		 * Skip these pages allocation here.

		 */

		if (!ms_hyperv.paravisor_present && !hv_root_partition) {

		if (!ms_hyperv.paravisor_present && !hv_root_partition()) {

			hv_cpu->synic_message_page =

				(void *)get_zeroed_page(GFP_ATOMIC);

			if (!hv_cpu->synic_message_page) {
@@ -272,7 +272,7 @@ void hv_synic_enable_regs(unsigned int cpu) 
	simp.as_uint64 = hv_get_msr(HV_MSR_SIMP);

	simp.simp_enabled = 1;



	if (ms_hyperv.paravisor_present || hv_root_partition) {

	if (ms_hyperv.paravisor_present || hv_root_partition()) {

		/* Mask out vTOM bit. ioremap_cache() maps decrypted */

		u64 base = (simp.base_simp_gpa << HV_HYP_PAGE_SHIFT) &

				~ms_hyperv.shared_gpa_boundary;
@@ -291,7 +291,7 @@ void hv_synic_enable_regs(unsigned int cpu) 
	siefp.as_uint64 = hv_get_msr(HV_MSR_SIEFP);

	siefp.siefp_enabled = 1;



	if (ms_hyperv.paravisor_present || hv_root_partition) {

	if (ms_hyperv.paravisor_present || hv_root_partition()) {

		/* Mask out vTOM bit. ioremap_cache() maps decrypted */

		u64 base = (siefp.base_siefp_gpa << HV_HYP_PAGE_SHIFT) &

				~ms_hyperv.shared_gpa_boundary;
@@ -367,7 +367,7 @@ void hv_synic_disable_regs(unsigned int cpu) 
	 * addresses.

	 */

	simp.simp_enabled = 0;

	if (ms_hyperv.paravisor_present || hv_root_partition) {

	if (ms_hyperv.paravisor_present || hv_root_partition()) {

		iounmap(hv_cpu->synic_message_page);

		hv_cpu->synic_message_page = NULL;

	} else {
@@ -379,7 +379,7 @@ void hv_synic_disable_regs(unsigned int cpu) 
	siefp.as_uint64 = hv_get_msr(HV_MSR_SIEFP);

	siefp.siefp_enabled = 0;



	if (ms_hyperv.paravisor_present || hv_root_partition) {

	if (ms_hyperv.paravisor_present || hv_root_partition()) {

		iounmap(hv_cpu->synic_event_page);

		hv_cpu->synic_event_page = NULL;

	} else {