Commit 797abd4e authored by Tao Su's avatar Tao Su Committed by Jason Zeng
Browse files

KVM: selftests: x86: Prioritize getting max_gfn from GuestPhysBits 

mainline inclusion
from mainline-v6.10-rc5
commit 980b8bc01938c8bcc9742c1051f64b5f0ed178ac
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/IB5K00
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=980b8bc01938c8bcc9742c1051f64b5f0ed178ac



---------------------------

Use the max mappable GPA via GuestPhysBits advertised by KVM to calculate
max_gfn. Currently some selftests (e.g. access_tracking_perf_test,
dirty_log_test...) add RAM regions close to max_gfn, so guest may access
GPA beyond its mappable range and cause infinite loop.

Adjust max_gfn in vm_compute_max_gfn() since x86 selftests already
overrides vm_compute_max_gfn() specifically to deal with goofy edge cases.

Intel-SIG: commit 980b8bc01938 KVM: selftests: x86: Prioritize getting max_gfn from GuestPhysBits

Reported-by: default avatarYi Lai <yi1.lai@intel.com>
Signed-off-by: default avatarTao Su <tao1.su@linux.intel.com>
Tested-by: default avatarYi Lai <yi1.lai@intel.com>
Reviewed-by: default avatarXiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20240513014003.104593-1-tao1.su@linux.intel.com


[sean: tweak name, add comment and sanity check]
Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarJason Zeng <jason.zeng@intel.com>
parent 0dfaa583

tools/testing/selftests/kvm/include/x86_64/processor.h

+1 −0
Original line number Diff line number Diff line
@@ -272,6 +272,7 @@ struct kvm_x86_cpu_property { 
#define X86_PROPERTY_MAX_EXT_LEAF		KVM_X86_CPU_PROPERTY(0x80000000, 0, EAX, 0, 31)

#define X86_PROPERTY_MAX_PHY_ADDR		KVM_X86_CPU_PROPERTY(0x80000008, 0, EAX, 0, 7)

#define X86_PROPERTY_MAX_VIRT_ADDR		KVM_X86_CPU_PROPERTY(0x80000008, 0, EAX, 8, 15)

#define X86_PROPERTY_GUEST_MAX_PHY_ADDR		KVM_X86_CPU_PROPERTY(0x80000008, 0, EAX, 16, 23)

#define X86_PROPERTY_PHYS_ADDR_REDUCTION	KVM_X86_CPU_PROPERTY(0x8000001F, 0, EBX, 6, 11)



#define X86_PROPERTY_MAX_CENTAUR_LEAF		KVM_X86_CPU_PROPERTY(0xC0000000, 0, EAX, 0, 31)

tools/testing/selftests/kvm/lib/x86_64/processor.c

+13 −2
Original line number Diff line number Diff line
@@ -1248,9 +1248,20 @@ unsigned long vm_compute_max_gfn(struct kvm_vm *vm) 
{

	const unsigned long num_ht_pages = 12 << (30 - vm->page_shift); /* 12 GiB */

	unsigned long ht_gfn, max_gfn, max_pfn;

	uint8_t maxphyaddr;

	uint8_t maxphyaddr, guest_maxphyaddr;



	max_gfn = (1ULL << (vm->pa_bits - vm->page_shift)) - 1;

	/*

	 * Use "guest MAXPHYADDR" from KVM if it's available.  Guest MAXPHYADDR

	 * enumerates the max _mappable_ GPA, which can be less than the raw

	 * MAXPHYADDR, e.g. if MAXPHYADDR=52, KVM is using TDP, and the CPU

	 * doesn't support 5-level TDP.

	 */

	guest_maxphyaddr = kvm_cpu_property(X86_PROPERTY_GUEST_MAX_PHY_ADDR);

	guest_maxphyaddr = guest_maxphyaddr ?: vm->pa_bits;

	TEST_ASSERT(guest_maxphyaddr <= vm->pa_bits,

		    "Guest MAXPHYADDR should never be greater than raw MAXPHYADDR");



	max_gfn = (1ULL << (guest_maxphyaddr - vm->page_shift)) - 1;



	/* Avoid reserved HyperTransport region on AMD processors.  */

	if (!host_cpu_is_amd)