Commit 3c5d19a3 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

Merge tag 'kvm-x86-guest-6.18' of https://github.com/kvm-x86/linux into HEAD 

x86/kvm guest side changes for 6.18

 - For the legacy PCI hole (memory between TOLUD and 4GiB) to UC when
   overriding guest MTRR for TDX/SNP to fix an issue where ACPI auto-mapping
   could map devices as WB and prevent the device drivers from mapping their
   devices with UC/UC-.

 - Make kvm_async_pf_task_wake() a local static helper and remove its
   export.

 - Use native qspinlocks when running in a VM with dedicated vCPU=>pCPU
   bindings even when PV_UNHALT is unsupported.
parents 473badf5 96055050

arch/x86/include/asm/kvm_para.h

+0 −2
Original line number Diff line number Diff line
@@ -124,7 +124,6 @@ bool kvm_para_available(void); 
unsigned int kvm_arch_para_features(void);

unsigned int kvm_arch_para_hints(void);

void kvm_async_pf_task_wait_schedule(u32 token);

void kvm_async_pf_task_wake(u32 token);

u32 kvm_read_and_reset_apf_flags(void);

bool __kvm_handle_async_pf(struct pt_regs *regs, u32 token);
@@ -148,7 +147,6 @@ static inline void kvm_spinlock_init(void) 


#else /* CONFIG_KVM_GUEST */

#define kvm_async_pf_task_wait_schedule(T) do {} while(0)

#define kvm_async_pf_task_wake(T) do {} while(0)



static inline bool kvm_para_available(void)

{

arch/x86/kernel/kvm.c

+30 −14
Original line number Diff line number Diff line
@@ -190,7 +190,7 @@ static void apf_task_wake_all(void) 
	}

}



void kvm_async_pf_task_wake(u32 token)

static void kvm_async_pf_task_wake(u32 token)

{

	u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);

	struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
@@ -241,7 +241,6 @@ void kvm_async_pf_task_wake(u32 token) 
	/* A dummy token might be allocated and ultimately not used.  */

	kfree(dummy);

}

EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);



noinstr u32 kvm_read_and_reset_apf_flags(void)

{
@@ -933,6 +932,19 @@ static void kvm_sev_hc_page_enc_status(unsigned long pfn, int npages, bool enc) 


static void __init kvm_init_platform(void)

{

	u64 tolud = PFN_PHYS(e820__end_of_low_ram_pfn());

	/*

	 * Note, hardware requires variable MTRR ranges to be power-of-2 sized

	 * and naturally aligned.  But when forcing guest MTRR state, Linux

	 * doesn't program the forced ranges into hardware.  Don't bother doing

	 * the math to generate a technically-legal range.

	 */

	struct mtrr_var_range pci_hole = {

		.base_lo = tolud | X86_MEMTYPE_UC,

		.mask_lo = (u32)(~(SZ_4G - tolud - 1)) | MTRR_PHYSMASK_V,

		.mask_hi = (BIT_ULL(boot_cpu_data.x86_phys_bits) - 1) >> 32,

	};



	if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT) &&

	    kvm_para_has_feature(KVM_FEATURE_MIGRATION_CONTROL)) {

		unsigned long nr_pages;
@@ -982,8 +994,12 @@ static void __init kvm_init_platform(void) 
	kvmclock_init();

	x86_platform.apic_post_init = kvm_apic_init;



	/* Set WB as the default cache mode for SEV-SNP and TDX */

	guest_force_mtrr_state(NULL, 0, MTRR_TYPE_WRBACK);

	/*

	 * Set WB as the default cache mode for SEV-SNP and TDX, with a single

	 * UC range for the legacy PCI hole, e.g. so that devices that expect

	 * to get UC/WC mappings don't get surprised with WB.

	 */

	guest_force_mtrr_state(&pci_hole, 1, MTRR_TYPE_WRBACK);

}



#if defined(CONFIG_AMD_MEM_ENCRYPT)
@@ -1072,16 +1088,6 @@ static void kvm_wait(u8 *ptr, u8 val) 
 */

void __init kvm_spinlock_init(void)

{

	/*

	 * In case host doesn't support KVM_FEATURE_PV_UNHALT there is still an

	 * advantage of keeping virt_spin_lock_key enabled: virt_spin_lock() is

	 * preferred over native qspinlock when vCPU is preempted.

	 */

	if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT)) {

		pr_info("PV spinlocks disabled, no host support\n");

		return;

	}



	/*

	 * Disable PV spinlocks and use native qspinlock when dedicated pCPUs

	 * are available.
@@ -1101,6 +1107,16 @@ void __init kvm_spinlock_init(void) 
		goto out;

	}



	/*

	 * In case host doesn't support KVM_FEATURE_PV_UNHALT there is still an

	 * advantage of keeping virt_spin_lock_key enabled: virt_spin_lock() is

	 * preferred over native qspinlock when vCPU is preempted.

	 */

	if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT)) {

		pr_info("PV spinlocks disabled, no host support\n");

		return;

	}



	pr_info("PV spinlocks enabled\n");



	__pv_init_lock_hash();