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Commit 67ec6607 authored by Joerg Roedel's avatar Joerg Roedel Committed by Avi Kivity
Browse files

KVM: SVM: Implement workaround for Erratum 383 



This patch implements a workaround for AMD erratum 383 into
KVM. Without this erratum fix it is possible for a guest to
kill the host machine. This patch implements the suggested
workaround for hypervisors which will be published by the
next revision guide update.

[jan: fix overflow warning on i386]
[xiao: fix unused variable warning]

Cc: stable@kernel.org
Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent fe5913e4

arch/x86/include/asm/msr-index.h

+1 −0
Original line number Diff line number Diff line
@@ -110,6 +110,7 @@ 
#define MSR_AMD64_PATCH_LOADER		0xc0010020

#define MSR_AMD64_OSVW_ID_LENGTH	0xc0010140

#define MSR_AMD64_OSVW_STATUS		0xc0010141

#define MSR_AMD64_DC_CFG		0xc0011022

#define MSR_AMD64_IBSFETCHCTL		0xc0011030

#define MSR_AMD64_IBSFETCHLINAD		0xc0011031

#define MSR_AMD64_IBSFETCHPHYSAD	0xc0011032

arch/x86/kvm/svm.c

+81 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 
#include <linux/ftrace_event.h>

#include <linux/slab.h>



#include <asm/tlbflush.h>

#include <asm/desc.h>



#include <asm/virtext.h>
@@ -56,6 +57,8 @@ MODULE_LICENSE("GPL"); 


#define DEBUGCTL_RESERVED_BITS (~(0x3fULL))



static bool erratum_383_found __read_mostly;



static const u32 host_save_user_msrs[] = {

#ifdef CONFIG_X86_64

	MSR_STAR, MSR_LSTAR, MSR_CSTAR, MSR_SYSCALL_MASK, MSR_KERNEL_GS_BASE,
@@ -374,6 +377,31 @@ static void svm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr, 
	svm->vmcb->control.event_inj_err = error_code;

}



static void svm_init_erratum_383(void)

{

	u32 low, high;

	int err;

	u64 val;



	/* Only Fam10h is affected */

	if (boot_cpu_data.x86 != 0x10)

		return;



	/* Use _safe variants to not break nested virtualization */

	val = native_read_msr_safe(MSR_AMD64_DC_CFG, &err);

	if (err)

		return;



	val |= (1ULL << 47);



	low  = lower_32_bits(val);

	high = upper_32_bits(val);



	native_write_msr_safe(MSR_AMD64_DC_CFG, low, high);



	erratum_383_found = true;

}



static int has_svm(void)

{

	const char *msg;
@@ -429,6 +457,8 @@ static int svm_hardware_enable(void *garbage) 


	wrmsrl(MSR_VM_HSAVE_PA, page_to_pfn(sd->save_area) << PAGE_SHIFT);



	svm_init_erratum_383();



	return 0;

}
@@ -1410,8 +1440,59 @@ static int nm_interception(struct vcpu_svm *svm) 
	return 1;

}



static bool is_erratum_383(void)

{

	int err, i;

	u64 value;



	if (!erratum_383_found)

		return false;



	value = native_read_msr_safe(MSR_IA32_MC0_STATUS, &err);

	if (err)

		return false;



	/* Bit 62 may or may not be set for this mce */

	value &= ~(1ULL << 62);



	if (value != 0xb600000000010015ULL)

		return false;



	/* Clear MCi_STATUS registers */

	for (i = 0; i < 6; ++i)

		native_write_msr_safe(MSR_IA32_MCx_STATUS(i), 0, 0);



	value = native_read_msr_safe(MSR_IA32_MCG_STATUS, &err);

	if (!err) {

		u32 low, high;



		value &= ~(1ULL << 2);

		low    = lower_32_bits(value);

		high   = upper_32_bits(value);



		native_write_msr_safe(MSR_IA32_MCG_STATUS, low, high);

	}



	/* Flush tlb to evict multi-match entries */

	__flush_tlb_all();



	return true;

}



static void svm_handle_mce(struct vcpu_svm *svm)

{

	if (is_erratum_383()) {

		/*

		 * Erratum 383 triggered. Guest state is corrupt so kill the

		 * guest.

		 */

		pr_err("KVM: Guest triggered AMD Erratum 383\n");



		set_bit(KVM_REQ_TRIPLE_FAULT, &svm->vcpu.requests);



		return;

	}



	/*

	 * On an #MC intercept the MCE handler is not called automatically in

	 * the host. So do it by hand here.